The global urban population is expected to continue growing rapidly. Enhancing the quality of life in urban areas will present an especially important challenge in the coming decades. This chapter describes how transport policy and investment can produce liveability benefits beyond reductions in carbon emissions and traffic congestion. The analysis quantifies the benefits of the High Ambition scenario relative to the Current Ambition scenario and isolates the effect of specific transport policies, such as carbon taxes and demand management, across several urban performance indicators.
ITF Transport Outlook 2023
ITF Transport Outlook
5. Liveable cities: The broader benefits of transport decarbonisation
Abstract
In Brief
Liveable cities provide their residents with easy access to the various opportunities an urban environment offers. Transport options therefore dramatically affect liveability. They contribute to the range of social activities accessible to city-dwellers but also to negative aspects such as the quantity of pollutants in air they breathe. Transport policies that reduce CO2 emissions and moderate travel demand can also make cities more liveable.
With the policies currently in place, emissions of toxic pollutants from city traffic are expected to grow over the coming decades in all but the high-income world regions, even as more fleets become cleaner. Substantially reducing transport-related pollutant emissions in urban areas requires ambitious fleet and demand policies. The combination of policies under the High Ambition scenario – including road pricing, fuel economy standards, green procurement and electrification of freight and passenger vehicles – can reduce CO2 emissions in urban areas by more than 78% by 2050 relative to 2019.
Encouraging active mobility is one important focus of urban decarbonisation policies. With this, however, the risk that pedestrians and cyclists will be exposed to conflicts with other road users is likely to rise. Mitigating or reversing this risk requires major investments in active mobility infrastructure and new restrictions on vehicle speeds in cities. By 2050, crash risk grows 4.5 times more under a continuation of today’s policies compared to the High Ambition scenario.
Transport will only be accessible and inclusive if it is affordable. Making shared modes more widely available in urban spaces can make them accessible to more users and combining this with integrated payment systems (including public transport and shared modes) will put them within reach of more users.
High-coverage public transport networks are a critical component of accessible and affordable urban mobility. Increased investment in public transport links connecting historically underserved neighbourhoods will address issues of inclusion and equity. By giving priority to public transport over cars, ambitious decarbonisation policies can shorten travel times for public transport users, making it more convenient to access opportunities across the city for those who do not drive.
Transport policy can also make cities more liveable by contributing to a more human-centric use of urban space. Space-efficient transport systems make room for more parks, new services and opportunities for recreational activities. The measures assumed in the High Ambition scenario would limit demand for private motorised transport and result in 2-10% lower road occupancy in 2050, compared to the Current Ambition scenario. Public support for such ambitious measures will be crucial to their acceptance and success.
Policy recommendations
Create attractive alternatives to private motorised vehicles to encourage the shift to sustainable transport and reduce pollution.
Consider equity impacts when developing new transport policies, investments and programmes.
Prioritise people, not vehicles, in urban design to improve safety for all road users.
Set ambitious goals for reducing pollutant emissions and take actions to achieve them.
Ensuring that emerging, ageing and growing urban areas continue to enable a high quality of life presents a global policy challenge and an opportunity. Interest in planning for liveable cities has grown substantially in recent years, due to a convergence of demographic and geographic trends. In 2014, the then United Nations Secretary-General, Ban Ki-moon, stated: “Liveable cities are crucial not only for city-dwellers but also for providing solutions to some of the key aspects of sustainable development” (United Nations, 2014[1]).
Transport affects almost every aspect of life. Because it enables access to opportunities, transport is inextricably connected to liveability. Moreover, transport systems indirectly affect other core components of liveability, including safety, social cohesion and the availability of public space. There are many views and definitions of liveability that vary across the globe (Paul and Sen, 2020[2]). Lowe et al. (2015[3]) define a liveable city as one whose neighbourhoods are:
“…safe, attractive, socially cohesive and inclusive, and environmentally sustainable; with affordable and diverse housing linked by convenient public transport, walking and cycling infrastructure to employment, education, public open space, local shops, health and community services, and leisure and cultural opportunities.” (Lowe et al., 2015[3])
This chapter focuses on the components of liveability most affected by transport: health and safety, access to opportunities, equitable mobility, and urban space. These four themes align with UN Sustainable Development Goal 11 (SDG 11), which calls on cities to provide “safe, affordable, accessible and sustainable transport” with an emphasis on road safety, air quality and disadvantaged populations (Hosking et al., 2022[4]). The following five sections explore each theme in detail. Note that transportation cannot contribute to all aspects of liveability: focusing on liveability as a planning process outcome risks contributing to gentrification and displacement (Tolfo and Doucet, 2022[5]). These are important urban issues but are not discussed in this chapter.
Cleaner air for healthier cities: The impact of transport on public health
The transport sector is a leading cause of many urban health concerns (Lowe et al., 2022[6]). Passenger and freight vehicles emit toxic pollutants into the atmosphere, including nitrous oxide, volatile organic compounds, and particulate matter. Public health indicators are widely used to evaluate the performance of transport systems; the global indicator framework for the UN SDGs includes transport-related outcomes such as exposure to fine particulate matter in urban areas (Giles-Corti, Lowe and Arundel, 2020[7]). The World Health Organization (WHO) estimates that 90% of the global population is exposed to significant air pollution (WHO, 2021[8]) and that air pollution is concentrated most heavily in urban areas.
Transport decarbonisation policies can reduce urban pollutant emissions
The ITF’s urban passenger model (see Chapter 2) measures the contribution of transport to public health using estimated urban pollutant emissions by region and by policy scenario. Pollutant emissions are a function of both the demand for transport and the characteristics of the vehicle fleet. The model includes separate indicators for six toxic pollutants emitted by transport vehicles: black carbon (BC), ammonia (NH3), nitrous oxide (NOx), fine particulate matter of 2.5 microns or less in diameter (PM2.5), sulphur dioxide (SO2) and volatile organic compounds (VOCs).
Figure 5.1. Evolution of urban pollutant emissions from 2019 to 2050 by scenario and region group
Note: Figure depicts ITF modelled estimates of the change in total annual air pollutant emissions (by mass) from passenger cars, light commercial vehicles, buses and heavy goods vehicles between 2019 and 2050 by scenario and region. Emissions from two- and three wheelers are not included. Values include only on-road emissions produced by urban transportation stemming from fuel burn. Current Ambition (CA) and High Ambition (HA) refer to the two main policy scenarios modelled, which represent two levels of ambition for decarbonising transport. BC: black carbon. NH3: ammonia. NOx: nitrous oxide. PM2.5: particulate matter. SO2: sulphur dioxide. VOC: volatile organic compounds. Estimates are by mass and are therefore not directly proportional to concentrations and urban air quality. Air-pollutant emissions estimated using fuel-pollutant factors (grams of pollutant per litre of fuel) provided by the International Council on Clean Transportation. Income classifications based on the World Bank’s World Development Index (2022[9]). A reporting region is denoted as “Low-income”, “Lower-middle-income”, “Upper-middle-income” or “High-income” based on the World Bank category into which the majority of the economies in the region fit.
These pollutants can have severe health impacts on urban residents and visitors alike. As highlighted in the ITF Transport Outlook 2021, NOx, SO2 and PM2.5 are notorious for their adverse effects on public health (ITF, 2021[10]). Note that the ITF model only estimates the tailpipe pollutants produced by burning fuel. It does not include additional pollutants generated by wear on tyres and brakes, or other vehicle components. The levels of BC, NH3, NOx, PM2.5, SO2 and VOC emissions from 2020 to 2050 evolve differently under the High Ambition and Current Ambition scenarios and between regions (see Figure 5.1).
As shown in Figure 5.1, high-income regions, which have relatively new vehicle fleets and transition to zero-emission technologies first, are expected to see significant drops in air pollutant emissions in the Current Ambition scenario. In the High Ambition scenario, emissions fall even faster, with a rapid transition to zero-emission vehicles (ZEVs) and alternative transport modes.
Middle-income regions are likely to experience higher levels of air pollution over time in the Current Ambition scenario, as increasing travel demand offsets the benefits from the gradual turnover of the vehicle fleet to newer vehicle technologies. Conversely, a rapid adoption of ZEV technologies and shifts away from private vehicles in the High Ambition scenario are likely to significantly improve air pollution levels.
Low-income regions are most at risk of significant increases in air pollution emissions due to the rapid increase in travel demand and a reliance on old, imported vehicle fleets with poor emissions control systems. Helping low-income regions transition towards lower-emission technologies and shift away from private passenger vehicles can halve the expected increases in many air pollutants under the High Ambition scenario.
Disaggregating the results by vehicle type illustrates just how difficult it will be to fully mitigate the public health risks caused by urban transport, even with ambitious policies. Heavy-duty vehicles, such as freight trucks and buses, produce approximately two thirds of NOx, BC, PM2.5 and SO2 urban air pollutants by mass, even though they only account for less than 5% of all vehicles on the road. Shifting urban transport to buses will play an important role in reducing private vehicle use. However, it is essential to also limit their air-pollutant emissions by renovating vehicle fleets and adopting new powertrain technologies.
Operators and transport authorities will need to address the logistical challenges of electrifying public transport, such as restructuring bus operations to account for the shorter range of battery electric buses relative to diesel buses and building maintenance and charging facilities for servicing battery electric buses (Sclar et al., 2019[11]). These results highlight how even an ambitious shift towards more sustainable modes such as public transport is a necessary but not sufficient condition for eliminating the public health risks posed by urban transport emissions.
Transport policies can target air pollution directly, for example through low-emission zones (LEZs) and zero-emission zones (ZEZs) where vehicles operate in zero-emission mode. London’s Ultra Low Emission Zone (ULEZ) is estimated to have reduced NOx emissions in the city centre by 31% in its first six months of operation, compared to a scenario in which the ULEZ did not exist (Greater London Authority, 2019[12]).
Similar restrictions on vehicle emissions have been enacted or planned in dozens of urban areas worldwide, although predominantly in Asia and Europe (Cui, Gode and Wappelhorst, 2021[13]). Implementation is often complex, and many jurisdictions have chosen to start with less onerous restrictions (e.g. time-specific restrictions or limits applied solely to freight vehicles) to test their design and build popular support. LEZ regulations may have distributional equity impacts by encouraging highly polluting vehicles to travel through other parts of an urban area. The equity impacts of LEZ regulations can be addressed through complementary policies, such as stringent vehicle emissions standards that limit the sale of highly polluting vehicles.
Low-emission vehicles are only one part of the solution
Not all air pollutants from tailpipe emissions are the by-products of burning fossil fuels. Some electric vehicles are crucial for limiting transport-related CO2 emissions but also release dangerous particulate matter into the atmosphere (OECD, 2020[14]). This example underscores the importance of considering urban liveability and climate change impacts when developing transport policy. Both public health and urban liveability would benefit from policies that limit travel distances through improved accessibility and encourage shifts towards active modes.
Shifting urban travel demand to active and shared modes that emit fewer pollutants per passenger will remain an important goal in creating healthy, liveable cities even after there are more electric vehicles in the fleet. Policies encouraging active travel can also lead people to exercise more often and improve health outcomes (Aldred, Woodcock and Goodman, 2021[15]). For example, a comprehensive review of the health and safety impacts of cycling found that the monetised health benefits from maintained or increased cycling-related physical activity outweighed the negative health impacts from crashes by up to a factor of 18:1 (OECD/ITF, 2013[16]). Box 5.1 summarises ongoing public health issues in urban areas and how active transport helps urban residents lead healthy lives.
Transport affects public health in several other important ways that the ITF model cannot measure. Mental health is one example. Stress caused by road congestion, fear of exposure to crime and violence during travel, and access to opportunities for social connection – all of which affect mental health – are related to the performance of the transport system (Whitley and Prince, 2005[17]; Mackett and Thoreau, 2015[18]; Nadrian et al., 2019[19]).
Furthermore, noise pollution generated by road, rail and air transport impairs cognitive functioning and increases stress levels, which leads to long-term physiological and psychological harm (Veber et al., 2022[20]). Decarbonisation measures, including vehicle electrification and active mode shift, have the co-benefit of reducing noise pollution from transport. These additional health impacts of transport, while not covered in detail in this report, should be considered as part of any holistic transport policy strategy.
The difference in pollutant emissions between the two policy scenarios explored in this edition of the Outlook is a stark example of how ambitious transport policy can bring benefits beyond addressing climate change and traffic congestion. The model estimates that the High Ambition scenario would result in 8.9 mega tonnes fewer NOx emissions in 2050 than under the Current Ambition scenario.
Based on the methodology used by Muller and Mendelsohn (2007[21]), these emission savings would produce an annual global public health benefit valued at USD 2.4 billion in 2050 due to reduced urban morbidity and mortality. When including the morbidity and mortality costs associated with NH3 (USD 3 810/tonne), PM2.5 (USD 3 000/tonne), SO2 (USD 1 360/tonne) and VOCs (USD 450/tonne), the value of the High Ambition scenario for public health alone is over USD 5.4 billion in 2050 relative to the Current Ambition scenario.
Designing safer streets: The link between traffic safety and decarbonisation
Approximately 1.3 million people are killed in road crashes annually (WHO, 2022[22]). Like urban air quality, road safety is a crucial component of liveability (ITF, 2021[23]). There is much potential for improvement over the status quo. Road deaths in urban areas have generally declined much more slowly relative to suburban and rural areas (ITF, 2021[23]). Traffic deaths persist in urban areas because urban streets feature a much greater share of cyclists, pedestrians, mopeds and other users exposed to higher-speed vehicle traffic.
A recent ITF study of 35 urban areas found that vulnerable road users made up 85% of all traffic fatalities (ITF, 2022[24]). Another contributing factor is the presence of large freight vehicles on urban streets, which can impede other uses and create safety hazards while picking up and delivering goods. While road safety reports typically focus on road fatality statistics because the data are more readily available, data on serious injuries, when available, provide additional insights into the overall safety of urban roads.
Box 5.1. The connection between transport planning and physical activity
Approximately one-third of all adults in OECD and European Union countries are insufficiently active, with national figures ranging from just under 20% of adults in Finland to up to 46% of adults in Portugal (OECD, 2021[25]). Low levels of physical activity reflect factors such as advances in communication technology and changes to the built environment that have given people fewer reasons to move (OECD, 2019[26]). For example, across the EU, cars are the predominant form of urban transport (Eurostat, 2021[27]).
Low levels of physical activity contribute to high rates of obesity, mental ill health, and illness, including cardiovascular diseases, commonly occurring cancers and type 2 diabetes. Several OECD countries have introduced policies to encourage active modes of transport to boost physical activity levels. These policies include investments in walking and cycling paths, green spaces and car-free zones.
As part of its Best Practices in Public Health project, the Health Division of the OECD’s Directorate for Employment, Labour and Social Affairs assesses the health, economic and mode-shift impacts of real-life initiatives promoting active transport modes, including the following examples from Denmark, France and Spain (OECD, 2022[28]).
Denmark: Cycle Superhighways
In 2009, Denmark introduced Cycle Superhighways, an intervention providing cyclists with infrastructure to ride safely between municipalities across the country. Cycle highways differ from regular cycling lanes as they are exclusively available to cyclists. Furthermore, cycle highways cover long distances and include maintenance stations for cyclists needing minor repairs or air pumps. Since 2010, on average, upgrading cycle routes to cycle superhighways has resulted in a 23% increase in cyclists, with 14% of new cyclists previously having travelled by car (Cycle Superhighways, 2019[29]).
Paris, France: Vélib’ Métropole
Vélib’ Métropole is one of the world’s first and largest bikesharing schemes. Created in 2007, Vélib’ (a portmanteau of the French words for bicycle and liberty) encourages residents to use active modes of transport more frequently. As of 2023, there were 1 800 Vélib’ bicycle stations across Paris and other parts of Île-de-France (the region around Paris, encompassing 60 municipalities). The stations provide access to 20 000 bikes, of which 40% are equipped with electric assistance technology (Vélib’, 2022[30]).
Barcelona, Spain: Superblocks
The Superblock model in Barcelona uses the city’s existing grid-like urban design to reorganise traffic circulation. Specifically, the intervention breaks Barcelona into several superblocks comprising nine blocks of enclosed inner streets that allow residents to drive in and out at a maximum speed of 10 kilometres per hour while restricting outside traffic from passing through. Estimates show that implementing Superblocks in all eligible regions in the OECD would, by 2050, reduce the incidence of disease by 1.8 million cases. As a result, Superblocks could lead to annual savings equivalent to 0.01% of total health expenditure in the Barcelona metropolitan region.
Source: OECD (forthcoming[31]).
Vulnerable road users face growing risks
Traffic safety for pedestrians and cyclists in urban areas could worsen over time. The risk will be higher if transport policies are limited to current climate commitments for modal shift without complementary policies to improve road safety. Figure 5.2 shows the anticipated trends for a proxy indicator for overall crash risk that captures the risk of potential conflicts between passenger vehicles and vulnerable road users. In the Current Ambition scenario, the risk of conflicts is expected to grow steadily until 2050, due to increasing pedestrian and cyclist volumes, and limited policies to protect them from conflicts with passenger vehicles.
Figure 5.2. Change in proxy indicator for crash risk over time under the Current Ambition and High Ambition scenarios
Note: Figure depicts ITF modelled estimates. The proxy indicator for crash risk measures the exposure to potential conflicts between vulnerable road users and passenger vehicles. It incorporates vehicle volumes, the difference in speed between modes and the degree of longitudinal separation between modes. Lower values represent less risk of exposure to conflicts. These indicators only account for conflicts with passenger cars, not freight vehicles. Current Ambition (CA) and High Ambition (HA) refer to the two main policy scenarios modelled, which represent two levels of ambition for decarbonising transport.
By 2050, the global average exposure risk will be nearly 60% higher than in 2019 under the Current Ambition scenario. The High Ambition scenario, which includes the rapid expansion of separated cycle lanes and vehicle speed restrictions, mitigates this rise in conflict exposure risk. Under the High Ambition policy bundle, the overall risk of exposure to conflicts grows more slowly than in the Current Ambition scenario. However, the growth in the risk indicator under both scenarios reinforces the importance of additional dedicated active travel and road safety policies as part of a Safe System approach (ITF, 2022[32]).
The proxy indicator for crash risk presented in Figure 5.2 and the mode-specific indicators in Figure 5.3 are new to the ITF Transport Outlook series. They estimate the risk of potential conflicts between pairs of travel modes (e.g. pedestrians and passenger cars) using the same street. The indicators account for total vehicle volumes, the difference in average travel speed between the modes, and the degree of longitudinal separation between the modes. However, they do not include potential conflict with urban freight vehicles.
The pedestrian-car and cyclist-car conflict safety indicators calculated for the Current Ambition and High Ambition scenarios make it possible to compare the effect of transport policies on exposure risk by region. The indicators are divided by total travel demand for the vulnerable mode to estimate the exposure risk per kilometre walked or cycled. A recent ITF report (2022[33]) provides a detailed methodology.
Figure 5.3. Change in pedestrian and cyclist safety indicators under the High Ambition scenario compared to the Current Ambition scenario in 2050
Note: Figure depicts ITF modelled estimates. The traffic safety indicator measures the exposure to potential conflicts between two travel modes. It incorporates vehicle volumes, the difference in speed between modes and the degree of longitudinal separation between modes. Negative values represent a reduced risk of exposure to conflicts. These indicators only account for conflicts with passenger cars, not freight vehicles. Current Ambition (CA) and High Ambition (HA) refer to the two main policy scenarios modelled, which represent two levels of ambition for decarbonising transport. ENEA: East and Northeast Asia. LAC: Latin America and the Caribbean. MENA: Middle East and North Africa. SEA: Southeast Asia. SSA: Sub-Saharan Africa. SSWA: South and Southwest Asia. TAP: Transition economies and other Asia-Pacific countries. UCAN: United States, Canada, Australia and New Zealand.
The results in Figure 5.3 show that ambitious decarbonisation policy measures are expected to reduce the exposure of vulnerable road users to crashes in urban areas compared to the Current Ambition scenario in most regions. The rapid expansion of footpaths and lower speed limits in the High Ambition scenario offset the increases in exposure for pedestrians in every region to some extent. The measures included in the High Ambition scenario mitigate an increase in the exposure to conflict and produce a safer street environment for pedestrians than the Current Ambition scenario. In Europe, Sub-Saharan Africa (SSA) and the TAP region, the exposure to conflicts for pedestrians falls by nearly 30% relative to the Current Ambition scenario.
Cyclists also see some level of improvement under the High Ambition scenario in most regions. They could expect a slight decrease in exposure to conflicts due to additional separated bike lane infrastructure and lower car speeds. However, the increase in mode share for cycling produces a greater risk of conflict exposure in two regions: the Middle East and North Africa (MENA) and Southeast Asia (SEA).
These trends suggest that the co-benefits of decarbonisation policies are not sufficient to address growing safety concerns for vulnerable road users. Some regions urgently require the rapid construction of infrastructure for vulnerable road users to keep pace with the growth in the number of cyclists and passenger vehicles on urban streets, along with stringent enforcement of speed limits. Urban areas where road networks are not yet mature should consider reserving some new infrastructure for light and active mobility. Additional road safety policies (e.g. on motorcycle helmets) will also be needed.
Ambitious policies can transform cities and increase safety for all road users
The results for the High Ambition scenario demonstrate how ambitious transport policies should play a transformative role in creating safer cities in all regions. Moreover, achieving the modal shift required to meet the policy goals of the High Ambition scenario will not be possible without investment in safer environments for walking, cycling, and light mobility more broadly.
Despite the benefits of the High Ambition policies for climate change, road safety for vulnerable users will decline substantially in many regions without additional policies that can improve urban traffic safety. The Safe System approach to road safety encompasses a wide variety of such policies. Under this framework, human error is considered inevitable. The joint design of infrastructure, traffic management, vehicles and post-crash care to eliminate death and serious injury as a consequence of human error complement the traditional policy emphasis on regulating behaviour. Thus, transport infrastructure design should work to minimise risks when crashes occur. Safe System design approaches include protected infrastructure for walking and cycling, traffic calming, improved road surface quality, and joint responsibility for the design and management of the road by all authorities involved (ITF, 2020[34]; ITF, 2022[32]).
The proxy indicator presented in Figure 5.3 captures the estimated exposure to potential conflicts but not the severity of these conflicts. Vehicle size and weight, like speed, are important factors in the severity of crashes involving vulnerable road users. Larger and heavier passenger vehicles have contributed to the alarming rise in severe injury and death rates among vulnerable road users in the United States (Edwards and Leonard, 2022[35]).
Vehicle weight considerations, especially for cars and vans, are critical as electric vehicles become more widespread; electric vehicles are often heavier than similarly sized fossil fuel-powered vehicles due to the added weight of the battery pack (OECD, 2020[14]). Weight-based fees for heavy passenger vehicles have been used to incentivise the purchase of lighter vehicles in France and in Washington, DC (Zipper, 2022[36]), and the European Union has begun to require protective measures for pedestrians and cyclists in new vehicle designs (ETSC, 2019[37]). Vehicle weight has increased over the past decades. Reversing this trend would significantly enhance vehicle efficiency, bring carbon dioxide (CO2) and pollutant reductions and contribute to road safety (ITF, 2017[38]).
Targeted road safety policies are needed to reduce risks
Designing safer streets involves reducing vehicle speeds and increasing the separation between vehicles and vulnerable road users. Lower speed limits should be combined with traffic-calming infrastructure and enforcement (Wilmot and Khanal, 2010[39]). Examples of traffic-calming infrastructure proven to reduce travel speeds include narrower travel lanes, chicanes and raised crosswalks (Damsere-Derry et al., 2019[40]). These treatments also have the benefit of inducing a shift towards sustainable modes by making them safer and, therefore, more attractive (Clarke and Dornfeld, 1994[41]). The ITF has recently published a guide to street design and traffic management solutions for safe streets (ITF, 2022[42]), which complements an extensive global guide by the World Resources Institute (Welle et al., 2015[43]). All urban road safety plans should take into account the evolution of both road fatalities and serious injuries.
Separated infrastructure for pedestrians and cyclists is a proven measure for reducing the rate of on-road injuries and fatalities (Reynolds et al., 2009[44]; Gössling and McRae, 2022[45]). Research has also shown that dedicated infrastructure is perceived by users as more comfortable and safe than high-volume shared lanes, and that more and targeted dedicated infrastructure encourages the adoption of active modes and micromobility (Clean Air Asia Center, 2013[46]; Ton et al., 2019[47]). Dedicated freight infrastructure (e.g. loading zones) that creates separation between freight vehicles and passenger vehicles can also be used to reduce conflicts, leading to improved overall traffic safety (McDonald and Yuan, 2021[48]).
In the future, the widespread adoption of autonomous vehicles could reduce or eliminate driver error as a cause of vehicle crashes. Automated vehicles may nonetheless display unanticipated and dangerous driving behaviours. Furthermore, technological progress has proven to be slower than expected, and considerable uncertainty remains around future adoption curves. Many forecasts expect it will be several decades before automated vehicles achieve high market penetration rates (Lavasani et al, 2016[49]). In the interest of maximising urban liveability in the short and long term, this section has focused primarily on opportunities to limit the frequency and severity of crashes involving human-operated vehicles.
Putting the city within reach: Transport policies for improving accessibility
A liveable city needs a transport system that performs its core function effectively: moving people around the urban area. This section analyses how cities and their transport systems can provide efficient access to the activities that residents want or need to pursue. These activities include necessities such as grocery shopping, work and health care, and urban amenities such as restaurants and entertainment. The section primarily focuses on “accessibility” in reference to access to opportunities, consistent with previous ITF publications on this topic (ITF, 2019[50]).
Reducing journey times for public transport expands access to opportunities
Demand for transport is typically derived, meaning that the need to travel usually results from the desire to pursue an out-of-home activity. The near-endless number of possible activities and work opportunities is one reason cities are such desirable places to live and why people continue to move to urban areas. Travelling to pursue activities at distant locations can be time-consuming, especially as urban areas grow larger and transport networks become congested. As a result, the inconvenient location of some activities can effectively render them unavailable.
The ability of residents to enjoy the benefits of urban living by travelling throughout an urban area is thus a function of the spatial accessibility the transport system enables. Moreover, certain destinations may only be accessible using specific travel modes (e.g. by driving a private car) and thus restricted to a subset of the population with access to that mode.
Many different indicators exist that quantify spatial accessibility. Weibull (1976[51]) proposed a set of technical criteria for any accessibility indicator: increasing attractions should improve accessibility; increasing travel times should reduce accessibility; and opportunities that do not provide value should not affect accessibility. Morris, Dumble and Wigan (1979[52]) also propose several practical criteria: an accessibility indicator should be based on behaviour, technically feasible, and easy to interpret.
The ITF Accessibility Framework (see Box 5.2) meets each of these criteria. It involves cumulative accessibility indicators that count the total number of destinations within a certain travel time threshold for each mode. Cumulative indicators are commonly used in comprehensive accessibility studies (Wu et al., 2021[53]). Proximity-based indicators are another means of measuring accessibility. Proximity-based accessibility indicators include the minimum travel time needed to reach the nearest activity location (e.g. a hospital) from a given origin location.
The ITF Accessibility Framework requires detailed transport network data for every urban area, which is not feasible to estimate as part of a global outlook. Instead, the Outlook uses two alternative indicators as a proxy for accessibility. The first is average travel speed by car and public transport. Travel speed by mode is used to illustrate how the performance of the transport system compares between policy scenarios. The second alternative indicator is the modal mix available in an urban area. This indicator evaluates the distribution of trips across mode categories to understand the potential impact of a disruption.
Figure 5.5 shows the average difference in journey time for passenger car and public transport between the Current Ambition and High Ambition scenarios in 2050 for each region. This indicator shows how long, on average, it takes to cross the city by each mode. The policies associated with the High Ambition scenario reduce the average journey time for public transport in every region except for SSA. These widespread benefits are unsurprising, given that many High Ambition policy measures directly aim to improve the performance of public transport systems. The decline in public transit speeds in SSA is roughly 5%.
Most regions could also expect an increase in average car journey times as road space is reallocated towards sustainable modes under the High Ambition scenario. Specific High Ambition policy measures, such as lower speed limits, could be expected to cause slower travel for passenger cars. Europe, MENA and UCAN see journey times improve for both cars and public transport. This is a combination of decreased congestion on the road network, caused by a steady modal shift to active and shared modes, and more opportunities available in close proximity due to changed land use planning practices.
This means that trip distances to access those opportunities will be shorter, although the journey time improvements in Europe, MENA and UCAN are still better for PT than for car. If the High Ambition policy measures are enacted, urban residents in these regions can expect more convenient travel by car and public transport, enabling them to reach more employment, social and recreational opportunities.
Box 5.2. Measuring accessible cities: The ITF Accessibility Framework
The ITF Accessibility Framework benchmarks the urban accessibility of the world’s cities (ITF, n.d.[54]). For a given location, it identifies how many destinations can be reached within a certain time by different travel modes: on foot, by bicycle, by public transport or by car. It then measures how many destinations lie within a certain geographic distance. The ratio of accessible destinations to nearby destinations determines the performance of each transport mode. This methodology for calculating accessibility differs from previous studies, as it captures transport performance independent of city size. It also uses a harmonised definition of a city that can be applied worldwide, providing a consistent benchmark for comparison.
An initial study (ITF, 2019[55]) used the framework to calculate accessibility to schools, hospitals, food shops, recreational opportunities and green spaces across 121 cities in 30 European countries (see Figure 5.4). It found that cities consistently offer higher accessibility than surrounding commuting zones. While cars provide better accessibility than public transport or cycling, especially for longer travel times and in commuting zones, bicycles and other micromobility modes perform better for trips of 15 minutes. Although congestion reduces transport performance, dense cities can still reach high levels of accessibility because many more destinations are located nearby. This underlines the fact that accessibility can be increased not only by policies that improve transport systems but also by policies that bring people closer to their destinations.
The ITF Accessibility Framework is now being improved and applied to different regions. In a collaboration with the OECD’s Sahel and West Africa Club, the ITF has measured the accessibility for walking, driving and informal public transport in Accra and Kumasi, Ghana’s two largest cities. The framework now uses gender-differentiated population and travel-behaviour data to capture gender differences in accessibility. For another study, the ITF is applying the framework to the Seoul Metropolitan Area in Korea. The study applies an equity lens by incorporating socio-economic population characteristics (e.g. age, gender, income and car ownership). Specific scenarios analyse the needs of particular population groups for access to essential destinations (e.g. access for the elderly to leisure facilities or access to jobs by public transport for lower-income households).
Figure 5.4. Visualising the accessibility of public transport for European cities
Note: The ITF Accessibility Framework visualisation tool, “How accessible is your city?”, enables comparison across cities. The five-coloured petals show the relative accessibility of population, schools, hospitals, food shops and green spaces, respectively, using public transport within a 30-minute travel time. The stem size and the number below each stem reflect the city’s overall accessibility score.
Source: ITF (n.d.[54]).
Figure 5.5. Change in journey time for passenger cars and public transport in 2050 from the Current Ambition to the High Ambition scenario, by region
Note: Figure depicts ITF modelled estimates. The average travel speed is calculated for a typical trip from the city centre to the edge of the urban area. Current Ambition (CA) and High Ambition (HA) refer to the two main policy scenarios modelled, which represent two levels of ambition for decarbonising transport. ENEA: East and Northeast Asia. LAC: Latin America and the Caribbean. MENA: Middle East and North Africa. SEA: Southeast Asia. SSA: Sub-Saharan Africa. SSWA: South and Southwest Asia. TAP: Transition economies and other Asia-Pacific countries. UCAN: United States, Canada, Australia and New Zealand.
Transport policy, accessibility and urban design are inextricably linked
Improving accessibility is increasingly recognised as a critical goal for urban planning (OECD, 2020[56]). Two popular urban design philosophies, transit-oriented development (TOD) and the “15-minute city”, seek to maximise access to opportunities through distinct but complementary approaches. The general goal of TOD is to create mixed-use communities within walking distance of a core commercial area that features a high-capacity transit station (Calthorpe, 1993[57]). A 15-minute city, on the other hand, is defined as an urban area where residents’ daily needs can be met by walking or cycling for no more than 15 minutes (Allam et al., 2022[58]).
In both concepts, the overarching emphasis is on sustainable mobility, mixed land-use development and reduced reliance on private motorised transport. Originally conceived as a sustainable option for suburban contexts in the United States, TOD focuses on public transport. In contrast, the 15-minute city relies on walking, cycling and micromobility as core modes providing access to nearby needs and amenities. TOD requirements in Dhaka’s development plans have been shown to create better access to a range of urban amenities across one of the world’s most densely populated cities (Rahman, Ashik and Mouli, 2022[59]).
Accessibility depends on the transport system’s effectiveness and the density of potential activities. Accessibility is also a function of congestion in the transport network and can vary by time of day. As discussed in Chapter 3, investment in efficient transport systems and policies that encourage short travel distances, such as compact land-use planning and robust public transit systems, are needed to produce highly accessible cities (Wu et al., 2021[53]).
The 15-minute cities and TOD concepts do not always improve urban equity, but their aims are often combined with social equity goals to ensure that all urban residents share the benefits (Lung-Amam, Pendall and Knaap, 2019[60]). Careful planning and complementary measures (e.g. inclusionary zoning to mitigate displacement of existing residents, social housing policies) are necessary to ensure that the benefits of accessible neighbourhoods are available to all. By reducing travel distances, improved accessibility facilitates a shift towards micromobility, active and shared modes, which are much more space-efficient. This mode shift allows for repurposing transport infrastructure for other uses, such as green space, which makes an urban area more liveable.
The transport system is only one element of accessibility. Therefore, this measure cannot reflect changes in land-use patterns. The policy measures in the High Ambition scenario, such as broader adoption of mixed-use development, would be expected to produce greater density and distribution of opportunities within an urban area. As a result, the change in travel speed between the Current Ambition and High Ambition scenarios is likely to underestimate the total improvement in urban accessibility produced by the High Ambition policy measures.
A mix of transport modes can improve liveability
The ITF has also developed a trip-based modal balance indicator to look at the diversity of modes available to urban inhabitants. The modal balance indicator is conceptually related to accessibility as it quantifies the transport network’s ability to provide access to opportunities under disruptions. Possible disruptions include inclement weather or crashes that impede travel. The indicator has been normalised on a scale from 0 to 1 such that a perfect balance of trips across travel mode categories would produce a score of 1, while total reliance on a single mode would produce a score of 0.
The modal balance in the United States, Canada, Australia and New Zealand (grouped in this report as the UCAN region) would notably improve under a High Ambition scenario compared to both the Current Ambition and current year scores (see Figure 5.6). Many North American cities are highly accessible by car but less accessible by public transport and active travel modes (Wu et al., 2021[53]). The overall accessibility of such cities for those who do not use cars is, therefore, poor. In addition, road network disruptions limit the transport accessibility of such cities, given the lack of alternative travel modes.
However, new mobility modes such as micromobility and shared mobility can improve accessibility and resilience by opening up a more comprehensive range of options to travellers, including adaptive vehicles for those with mobility impairments (Abduljabbar, Liyanage and Dia, 2021[61]). The regional benefits observed in UCAN are a product of a shift away from overreliance on private cars, which account for more than 80% of trips in 2022, to a greater share for metro and active modes.
An urban area would be quite vulnerable to a severe disruption to the road network if passenger cars were the overwhelmingly dominant travel mode and other modes lightly used or unavailable. More even modal balance would help to limit the impact of a disruption to the road network in the UCAN region, which is critical for climate adaptation. For Europe, LAC and MENA, the modal balance indicator is largely unchanged between 2022 and 2050, and the High Ambition policy measures have little effect. Other regions, such as ENEA and UCAN, see an improvement in modal balance due to the High Ambition policies.
Figure 5.6. Changes to regional modal balance between 2022 and 2050
Note: Figure depicts ITF modelled estimates. This indicator measures the trip-based modal balance across four categories of modes, where 1 represents a perfect balance across all mode categories and 0 represents all trips within a single mode category. The mode categories are light road users (walking, cycling, motorcycles, three-wheelers, scooter sharing, bikesharing and motorcycle sharing), heavy road vehicles (cars, taxis, buses, informal buses, ridesharing, carsharing and taxi buses), light public transport (bus rapid transit and light-rail transit), and heavy public transport (suburban rail and metro). Current Ambition (CA) and High Ambition (HA) refer to the two main policy scenarios modelled, which represent two levels of ambition for decarbonising transport. ENEA: East and Northeast Asia. LAC: Latin America and the Caribbean. MENA: Middle East and North Africa. SEA: Southeast Asia. SSA: Sub-Saharan Africa. SSWA: South and Southwest Asia. TAP: Transition economies and other Asia-Pacific countries. UCAN: United States, Canada, Australia and New Zealand.
In the SEA, SSA and South and Southwest Asia (SSWA) regions, the High Ambition policy measures reduce the modal balance indicator relative to the Current Ambition scenario. This is because the High Ambition policies boost the already disproportionate shares of walking, cycling and other forms of micromobility in these regions.
These results demonstrate how policies that produce a more sustainable modal split can also result in a concentration of trips across similar modal categories. Infrastructure disruptions are less likely to be a concern because these modes are relatively nimble compared to large buses or rail vehicles. However, active and other non-active micromobility modes may be affected by inclement weather, so maintaining convenient alternatives such as public transport is essential for the robustness of the transport system.
The High Ambition measures, including increased availability of shared modes, better infrastructure for active and non-active micromobility modes, and mixed-use development, result in a smaller role for informal bus transport in emerging economies relative to the Current Ambition scenario. Informal buses are quite flexible and address a critical market need in many urban areas. However, their travel times can also be unreliable, and vehicles are often overcrowded (Sohail, Maunder and Cavill, 2006[62]).
Making lighter shared and active vehicles available for some trips is expected to complement the informal bus network and provide new transport options for short and medium-length trips (Loo and Siiba, 2019[63]). For example, users described a public bikeshare system, introduced in Manila in 2015 to provide an alternative to informal buses for university students, as “reliable”, “comfortable” and “convenient” (Sharmeen, Ghosh and Mateo-Babiano, 2021[64]). Mixed-use development would allow people to pursue a wider range of activities close to home, thus making active modes more attractive and reducing the mode share of informal buses (Rahman et al., 2023[65]).
One crucial consideration when quantifying modal balance is the choice of categories. Different modal categories will measure vulnerability to different types of disruptions. For example, the indicator used in this chapter uses categories based on their ability to respond to infrastructure disruptions: light road users (e.g. walking, motorcycles and micromobility), heavy road vehicles (e.g. cars, taxis and buses), light public transport (including bus rapid transit (BRT) and light-rail transit) and heavy public transport (metro and suburban rail). These categories produce an indicator that measures the vulnerability of regional transport systems to infrastructure-related disruptions. Another option would be to categorise modes based on ownership (e.g. shared, private or public modes). Such an indicator could help evaluate the vulnerability of a transport system to disruptions in funding sources, such as the failure of a private bikesharing operator or discontinued subsidies for public transport.
Recent lifestyle changes have mixed impacts on accessibility and liveability
Emerging technologies and social trends have begun to change how public officials and scholars measure urban accessibility. The first is the substitution of in-person shopping by e-commerce. In one sense, this has improved accessibility for the shopper by eliminating travel time for shopping trips. A trip by the delivery platform is still required, however. As a result, e-commerce is not simply an unconditional improvement in liveability. Still, under the right circumstances, e-commerce platforms can efficiently meet people’s needs while reducing overall travel. Policies that strongly incentivise sustainable, efficient and safe urban freight networks ensure that deliveries do not increase urban greenhouse gas emissions or traffic congestion.
The ITF model results show that ambitious freight policies can reduce urban freight vehicle-kilometres for parcel deliveries. The results for this Outlook show that asset sharing across operators, which has been shown to improve freight efficiency in the past (Vanovermeire et al., 2014[66]), produces a 23% reduction in urban package vehicle-kilometres relative to a baseline scenario with no asset sharing. Consolidated package pickup and drop-off locations (also referred to as “package lockers”) reduce vehicle-kilometres by 27% compared to the baseline scenario with only door-to-door deliveries. While large platforms have succeeded in consolidating orders from small vendors to improve operational efficiency, asset sharing across platforms has not achieved widespread adoption in practice (Karam, Reinau and Østergaard, 2021[67]).
Shifting last-mile deliveries to cargo bikes for feasible trips reduces motorised VKM by 35%, although overall VKM increases due to a significant increase in non-motorised trips. Non-motorised freight modes such as cargo bikes have a smaller impact on urban safety, air pollution levels and space consumption. Therefore, they represent a liveability improvement relative to large, motorised freight modes.
The second emerging trend is the rise in remote work catalysed by the Covid‑19 pandemic. Remote work is similar to e-commerce in that it has made access to some forms of work possible without the need to travel. This improvement in accessibility comes without changing the transport system or land use. Nevertheless, an uptake of remote work may not always improve liveability. Many remote workers have moved away from city centres as they no longer need to commute five days per week (Ramani and Bloom, 2021[68]). There are often fewer options for sustainable travel in suburban and rural areas, so these remote workers may begin to drive more often and further than before, increasing their carbon footprints.
Even for remote workers who continue to make sustainable travel choices, the lack of a commuting trip to anchor the daily travel schedule can induce multiple shorter trips for other daily activities (Budnitz, Tranos and Chapman, 2020[69]; Wöhner, 2022[70]). Land-use policies that allow these activities to take place close to home would mitigate the impact of remote work on liveability. Improving urban accessibility to meet the daily travel needs of remote workers is a new and challenging task for planners and policy makers. A recent ITF report (2023[71]) offers specific actions for adapting to these emerging mobility patterns.
Liveability for all: Promoting equitable and inclusive transport
Transport policy helps guide the allocation of scarce resources through public investment in infrastructure and operations. As transport is inherently place-based, resource allocation choices are likely to benefit some urban residents over others. Social equity, described as the fair and appropriate distribution of costs and benefits within society, is an essential component of transport policy. In the context of liveability and transport, “fair and appropriate” means that every neighbourhood should have similarly convenient access to activities. It also means that the negative externalities of transport should be shared across the urban area. A broad distribution of amenities allows all residents to flourish as individuals while creating social cohesion and a sense of community.
Equitable transport policy addresses past injustices
Equity is a broad term that encompasses many different ideas. The concept of transport equity has become increasing prominent in planning and policy discussions, but the impacts of a long legacy of inequitable policies are still felt today. The concentration of environmental burdens is one example. Communities that experience disproportionate environmental harms and risks due to transport infrastructure are often referred to as “environmental justice communities” in the United States and increasingly around the globe (Correa, 2022[72]).
Certain countries and regions have taken proactive measures to reduce the number and extent of such communities, including prioritising the construction of new sustainable transport infrastructure in designated areas (Louis and Skinner, 2021[73]). Other past policies have created communities that are disproportionately affected by a lack of transport investment relative to the rest of the urban area (Amar and Teelucksingh, 2015[74]) or that have suffered displacement due to the construction of new transport infrastructure (Perry, 2013[75]).
Another important aspect of transport equity is “vertical transport equity”, which assumes that fairness involves providing treatment to improve the conditions of disadvantaged and underserved people (Di Ciommo and Shiftan, 2017[76]). There are many dimensions of vertical transport equity. For example, vertical transport equity with respect to income would involve policies specifically designed to reduce the transport cost burden for lower-income travellers, such as investment in affordable modes or income-based fare subsidies for public transport (Rosenblum, 2020[77]).
Racial and gender transport equity addresses past injustices that disproportionately affect certain groups. Transport is not gender-neutral (ITF, 2019[78]). Integrating gender differences into transport planning remains a relatively uncommon practice despite known disparities in needs and outcomes (Carvajal and Alam, 2018[79]). In 2022, as part of a research workstream dedicated to gender equity, the ITF launched a Gender Analysis Toolkit for Transport Policies. The toolkit provides a resource for introducing gender equity considerations into transport policy development (ITF, 2022[80]). Evaluating transport investments and policies through a racial equity lens is also becoming more widespread (Verlinghieri and Schwanen, 2020[81]).
Transport affordability is a crucial component of equity
Another important equity consideration is the relative affordability of travel by mode. Policies that reduce the generalised cost of travel also lessen the financial and time burden placed on lower-income households and make more opportunities available for the same travel cost. Improved affordability has a similarly positive effect on liveability: improved accessibility for lower-income households is an example of vertical transport equity concerning income. Many transport policy measures (e.g. road pricing and low-income fare discounts) directly impact affordability. Integrated public transport ticketing also affects affordability by reducing the time cost (and, in some cases, the fare) of transfers between modes.
The ITF model estimates the generalised cost of an average trip for different modes, which incorporates both the travel time and the financial cost. Financial costs involve fares for public transport and shared modes, and operating and maintenance costs for private modes, including any pricing measures. These trip costs are then normalised by regional per-capita gross domestic product (GDP) to estimate the relative affordability of travel by mode.
Figure 5.7 illustrates how policy measures that improve the integration of public transport and shared modes could affect trip affordability in different regions by 2050. Making shared mobility vehicles more widely available and increasing the availability of mobility-as-a-service subscriptions and pay-as-you-go models have a strong impact on the affordability of bikesharing and carsharing. Increasing the number of available vehicles reduces the time cost of accessing a vehicle, thus improving affordability.
At the same time, multi-modal travel services, such as Mobility as a Service, are expected to increase the demand for shared mobility, resulting in operational efficiencies passed on to the user through lower fare costs. As discussed in Chapter 3, this will be contingent on viable business models being identified. Trip costs for bikesharing decrease by more than 25% in the Latin America and the Caribbean (LAC), MENA, SSWA and TAP regions. Policies encouraging mobility-as-a-service adoption also decrease trip costs for public transport modes in nearly all regions. Furthermore, shared mobility policies indirectly make private car trips somewhat less affordable due to greater competition for road space.
Equity can also apply to the distribution of investment by travel mode. Modal equity is a necessary but not sufficient condition for transport equity (Pereira and Karner, 2021[82]). The United States spends nearly 90% of its transport infrastructure investment on automobile infrastructure (OECD, 2022[83]). As a result, there are often few independent travel options for seniors, adolescents, lower-income households, people with disabilities and other non-drivers (Litman, 2022[84]). Automobile dependency thus forces those who prefer alternative modes into car ownership, or to make other compromises. In contrast, several European countries invest over half of their transport budget on new rail infrastructure (OECD, 2022[83]), which includes urban passenger rail, a mode that is often less expensive on a per-trip basis and accessible to all.
The shared mobility mode share varies across regions, partially due to the uneven availability of certain shared mobility modes in cities in emerging economies (Venter, Mahendra and Hidalgo, 2019[85]). As a result, the accessibility benefits of shared mobility are not equitably distributed across regions. One approach to encouraging modal equity requires that future street maintenance and reconstruction projects integrate multimodal infrastructure. The City of Cambridge, Massachusetts, has taken this approach in its 2019 Cycling Safety Ordinance (City of Cambridge, 2019[86]), which states that cycle lanes must be included in street reconstruction plans.
Equity principles also apply to transport investment and outcomes across metropolitan areas, countries and regions. This is often referred to as spatial or territorial equity. Territorial equity is especially significant for urban transport due to the vast regional differences in transport availability, performance and exposure to negative externalities highlighted throughout this report.
Figure 5.7. Sensitivity of trip affordability to public transport and shared-mode integration policies in 2050, by region and mode
Note: Figure depicts ITF modelled estimates. Trip affordability is defined as the average cost per trip divided by the average per-capita GDP for each region. The operational efficiency policy measures used for the sensitivity analysis are 1) integrated public transport ticketing, 2) increased availability of shared mobility vehicles, 3) increased availability of mobility-as-a-service platforms and 4) increased availability of carpooling. ENEA: East and Northeast Asia. LAC: Latin America and the Caribbean. MENA: Middle East and North Africa. SEA: Southeast Asia. SSA: Sub-Saharan Africa. SSWA: South and Southwest Asia. TAP: Transition economies and other Asia-Pacific countries. UCAN: United States, Canada, Australia and New Zealand.
The results in Figure 5.7 show how the outcomes of transport policies can vary by region. For example, the affordability of urban public transport modes such as buses, BRT and metro improves most in regions with expansive formal public transport networks. Policies such as integrated ticketing and shared modes for first- and last-mile access are less helpful where formal public transport systems are limited.
Addressing historical imbalances in public transport investment across regions would not only improve the overall quality of the transport system; it would also allow more cities to reap the affordability and liveability benefits of ambitious transport policies. An example of territorial equity applied to transport policy is the European Union’s Trans-European Network for Transport, whose objectives include the “reduction of infrastructure quality gaps between Member States” (Aparicio, 2018[87]).
Transport for inclusive societies
People with disabilities have long been excluded from using certain transport modes. Physical barriers, including stairs for accessing public transport and poorly maintained footpaths, often limit access to opportunities for those with mobility and visual impairments. Many cities have enacted policies to improve the physical accessibility of public transport. Still, much work remains to be done to ensure that the advantages of public transport are broadly shared (Bezyak, Sabella and Gattis, 2017[88]).
Micromobility and many shared mobility vehicles and interfaces can be similarly inaccessible for urban residents with disabilities. Regulations that require new mobility operators to provide inclusive or adaptive vehicles as part of their operating fleet have proven moderately successful (LaRosa and Bucalo, 2020). Further public policy work is needed to improve the distribution of inclusive and adaptive vehicles across shared mobility fleets.
Ageing populations are another vulnerable group with limited transport options. Urban populations have grown older in developed and emerging economies alike and are expected to continue ageing in the coming decades (OECD, 2015[89]; UN DESA, 2022[90]). Cities will need to adapt to meet the needs of older residents and improve liveability. Many of the transport policies that improve liveability for those with mobility impairments will also benefit seniors, such as the removal of physical barriers and inclusive design for mobility platforms. Providing quiet public spaces for people to sit down, rest and socialise during travel is also recommended to improve access and make travel easier for the elderly (Yung, Conejos and Chan, 2016[91]).
Prioritising urban space for people: Creating a space-efficient transport system
Space is in high demand in most cities: space is needed for housing, infrastructure, commercial activities and the many other uses that define an urban area. As evidenced by the definitions of liveability provided at the beginning of this chapter, truly liveable cities allocate a considerable amount of their available space to public amenities. Liveability-enhancing amenities include urban parks, community gathering places and public services. Appleyard (1980[92]) describes how even small changes to urban space can improve liveability by producing more socialisation opportunities. Yet once urban development has taken place, it can often be difficult or expensive to reclaim land for public amenities.
Ambitious decarbonisation policies can reduce congestion and limit the space consumed by transport
One method for estimating the change in space consumption that results from transport policies is to quantify the fraction of the urban road capacity used by transport (i.e. road occupancy). When a smaller share of the road space is needed to support travel demand, excess travel lanes can be converted to support uses that improve liveability. The ITF Transport Outlook model estimates road occupancy by dividing the on-street traffic volumes by the capacity of the available road network. Using road occupancy as a proxy measure for street space use is likely to underestimate the magnitude of space consumption changes. It does not consider changes to on-street parking demand that would also result from large-scale modal shifts.
ENEA, one of the regions experiencing the most congestion in 2022, is expected to see significant reductions in road occupancy by 2050 (see Figure 5.8) under both policy scenarios. Due to rising urbanisation and limited mode shift to more efficient travel modes, a range of increases in urban road occupancy are anticipated for the MENA, SSWA and UCAN regions under Current Ambition policies. The SSWA region will become more congested than any other region in the Current Ambition scenario, but it also benefits the most in 2050 from the High Ambition scenario in terms of the level of reduced congestion.
In 2050, across all regions, the more ambitious transport policies enacted in the High Ambition scenario deliver a substantial reduction in road occupancy compared to the Current Ambition scenario. For the MENA and SSWA regions, the High Ambition policies are sufficient to offset the anticipated increases in road congestion under the Current Ambition scenario and produce less congested roads in 2050 relative to 2022. The only region that is expected to see greater congestion in 2050 under both scenarios is UCAN.
While the percentage changes in Figure 5.8 may appear relatively small, they represent a meaningful shift in the total amount of land needed for transport. The UN Human Settlements Programme provides a harmonised measure for the percentage of urban land dedicated to streets (UN-Habitat, 2013[93]). Large cities such as Chicago and Delhi dedicate over 20% of their total land area to streets (Meyer and Gómez-Ibáñez, 1981[94]; Cervero, 2013[95]). Even in a city with a relatively low proportion of street area, such as Dhaka, the 9.6% reduction in occupancy afforded by the High Ambition scenario would result in over 270 urban hectares becoming available for other uses, including much-needed green space (Labib, Mohiuddin and Shakil, 2013[96]).
Figure 5.8. Percentage occupancy of total urban road capacity in 2050 under the Current and High Ambition scenarios, compared to 2022
Note: Figure depicts ITF modelled estimates. Percentages indicate the reduction in road capacity used under High Ambition scenario compared to Current Ambition scenario. Current Ambition (CA) and High Ambition (HA) refer to the two main policy scenarios modelled, which represent two levels of ambition for decarbonising transport. ENEA: East and Northeast Asia. LAC: Latin America and the Caribbean. MENA: Middle East and North Africa. SEA: Southeast Asia. SSA: Sub-Saharan Africa. SSWA: South and Southwest Asia. TAP: Transition economies and other Asia-Pacific countries. UCAN: United States, Canada, Australia and New Zealand.
The two primary means of reducing space consumption by transport are: 1) incentivising travel modes with lower space consumption per person per trip and 2) increasing the occupancy rates of shared vehicles. Private cars are the predominant travel mode in many upper-income cities, but they are also the least space-efficient for an average single-occupant trip. As a result, there is an opportunity to reduce space consumption by a significant margin. High-capacity public transport vehicles, including buses, trams and passenger trains, require much less space to serve each trip than private cars.
Active transport modes such as cycling and walking, while less practical for long-distance trips, consume much less space per person than the average private car. Ridesourcing and vehicle-sharing platforms, when subject to policies that provide incentives for higher usage, can also reduce space consumption and congestion relative to private cars (Lazarus et al., 2021[97]). These alternative modes also significantly reduce the need for parking at the destination, making it possible to convert public parking spaces to alternative uses.
Recent ITF work on policies to improve space efficiency within urban areas (ITF, 2022[98]) makes it easier to estimate the amount of space consumed by urban passenger transport. Figure 5.9 illustrates how ambitious transport policies will affect the static and dynamic space consumed by passenger transport in 2050. The static space indicator complements the congestion indicator by estimating the space needed for vehicle parking and storage based on mode choice and demand. The dynamic space indicator, on the other hand, estimates the space consumed by traffic. Figure 5.9 shows how both the static and dynamic space consumed by passenger transport reduces under the High Ambition scenario in 2050.
Large cities are already more efficient in their use of space. Car ownership in larger cities is generally less than the national average, and the amount of street space per inhabitant is a fraction of that in smaller cities. Medium-sized and small cities tend to have less dense public transport networks and fewer alternatives to the car. Therefore, although they can save space under the High Ambition scenario, they will still dedicate more street space per capita to passenger mobility than in larger cities.
For most regions, the greatest reductions in space consumption come from reduced on-street parking allocation (see Figure 5.9). Such restrictions reduce the dominance of cars and private motorised vehicles in the streetscape. In UCAN countries, the car is expected to remain a core part of the future urban mobility mix, even under the High Ambition scenario (see Chapter 3). This helps explain the low levels of savings in terms of space consumed by passenger transport in urban areas in these countries for all city sizes.
Shared mobility in very large, developed cities in regions such as Europe or UCAN can decrease the dynamic and static space consumption of passenger travel through increased load factors and reduced standing-time for the vehicles. In emerging regions, shared mobility offers the opportunity to advance a public-like transport system more quickly than would be possible relying solely on development of public transport infrastructure.
Increasing average vehicle occupancy rates could reduce the space consumption of shared modes by serving the same number of trips with fewer vehicles. Promoting carpooling among commuters with similar travel patterns (e.g. via digital driver-passenger matching platforms) is one approach to boosting occupancy rates for private vehicles. Ride-hailing and taxi services also suffer from low average occupancy and spend considerable time cruising for new passengers while unoccupied. Occupancy performance incentives, distance-based fees or other regulations could help address these issues (ITF, forthcoming[99]).
Figure 5.9. Percentage change in static and dynamic urban space consumed by passenger transport in 2050, High Ambition scenario relative to Current Ambition scenario, by city size
Note: Figure depicts ITF modelled estimates. Results reflect the dynamic and static space consumption of passenger vehicles and do not include freight vehicles. For details of the methodology used to calculate space consumption see ITF (2022[98]). Dynamic space refers to the space consumed by traffic. Static space refers to the space consumed on a permanent basis for the use of passenger modes (e.g. parking spaces). City sizes refer to the size of the population of the city: Large: more than 5 million inhabitants; Medium: between 1 million and 5 million inhabitants; Small: fewer than 1 million inhabitants. ENEA: East and Northeast Asia. LAC: Latin America and the Caribbean. MENA: Middle East and North Africa. SEA: Southeast Asia. SSA: Sub-Saharan Africa. SSWA: South and Southwest Asia. TAP: Transition economies and other Asia-Pacific countries. UCAN: United States, Canada, Australia and New Zealand.
The demand for street space is not limited to passenger transport; urban freight is a large and growing consumer of on-street and curb space. Delivery vehicles are often large and must park for extended periods to pick up goods and make deliveries, consuming considerable amounts of road space within urban areas. There are, however, some promising experiments to encourage the use of smaller vehicles that can easily navigate urban areas. Many cities, including Amsterdam, Bogotá and New York, have deployed electric cargo bike pilot programmes for last-mile goods delivery. These pilots have made deliveries more efficient under certain conditions (ITF, 2022[33]). Box 5.3 provides an overview of the challenges associated with urban freight and several potential solutions to reducing space consumption.
Less space for transport means more space for public amenities
Approaches to increasing urban amenity space include using the existing transport infrastructure more efficiently and freeing up the land occupied by transport for alternative uses. One example is the conversion of on-street parking spaces into temporary restaurant seating, which occurred in many cities during the Covid‑19 pandemic (O’Sullivan, 2021[100]). These micro-interventions collectively improved the quality of life of urban residents during the public health crisis (Marks, 2021[101]).
Space conversions can also be more extensive; the city of Seoul has removed 15 elevated expressways since 2002 replacing them with parks and bike lanes and restoring access to an existing stream. These efforts have reduced summer temperatures by more than 3 degrees Celsius in some areas, providing public health benefits for residents (Mesmer, 2014[102]). Similarly, highway removal projects in Spain, Colombia and the United States have made urban areas more liveable by reducing air and noise pollution, lowering crime and providing access to new public spaces (ITDP, 2012[103]; Khalaj et al., 2020[104]).
Box 5.3. The urban freight “space race”
Freight transport activities are a significant and growing competitor for urban street space. Global urban freight demand is expected to double by 2050, accounting for more than 15% of total vehicle-kilometres travelled in many urban areas (ITF, 2021[10]). There are opportunities to reduce the space consumed by parked and moving freight vehicles, for example by managing the types of vehicles used for freight activities (see Figure 5.10).
Figure 5.10. Static and dynamic space usage by freight vehicle type
Note: The dimensions indicated in the figure are (a) vehicle length, (b) dynamic space consumed and (c) static space consumed.
Source: (ITF, 2022[33]).
The ITF has investigated the implications of more than 20 policy measures to improve urban freight vehicles’ use of street space by simulating transport activities in a medium-sized urban area (ITF, 2022[33]). The simulations showed that voluntary private-led measures would reduce freight trips by 11%.
In contrast, when public authorities intervene to incentivise space-efficient urban freight distribution, the use of space decreases by more than 30%. Public action is essential for managing freight demand and the timing of deliveries, as is the dynamic allocation of street space for both passenger and freight flows. Fostering shared mobility and integrating some freight and passenger flows could improve space efficiencies by a further 16%.
Policies targeting the use of urban space by freight activities also have substantial liveability co-benefits. Improved load factors, increased use of lighter and smaller vehicles, and electrification could reduce carbon dioxide (CO2) emissions by more than 60%. Emissions of nitrous oxide (NOx), fine particulate matter of 2.5 microns or less (PM2.5) and sulphur dioxide (SO2) would decrease by 78%, 90% and 100%, respectively.
These policies can also improve road safety. In the most ambitious scenario, the exposure risk of conflicts between freight vehicles and pedestrians decreases by more than 40%. In comparison, the exposure risk of conflicts between freight vehicles and cyclists decreases by 60%.
The report makes three recommendations. First, take passenger and freight activities into account when managing curb space, and provide additional curb space for freight vehicles, especially smaller vehicles such as cargo bikes. Second, extend access restrictions to freight services while accounting for the needs of freight carriers. Third, public authorities should develop tools, capacities, partnerships and comprehensive plans to monitor and respond to the complex and rapidly evolving urban freight system.
Ongoing urbanisation, the effects of climate change, and the threat of global pandemics will make urban amenities even more critical in the future. As demonstrated in Seoul, urban green spaces help mitigate climate change effects and improve air quality while offering a cool respite from warming ambient temperatures. Elsewhere, cities are using reclaimed urban space to build flood protection systems, rain gardens and similar climate change adaptation (Kasprzyk et al., 2022[105]).
Amenities that offer opportunities for recreation and socialising will be even more important in rapidly growing urban areas, where homes and apartments are often smaller. The experience of Covid‑19 has also demonstrated how outdoor urban space could provide a safe place for physical activity during a global pandemic when indoor group exercise is not permitted.
Pilot programmes demonstrating how urban space can be reimagined are often helpful in generating public support. Urban residents and visitors will not experience the liveability benefits of reduced space consumption unless there is political will to reallocate the space for public use. Temporary pilot programmes can illustrate the benefits and dispel concerns about the downsides of street-use changes. During the Covid‑19 pandemic, many cities introduced temporary changes in street use, such as bike lanes in Mexico City (ITDP, 2021[106]) and expanded outdoor dining in Paris (O’Sullivan, 2021[100]), which subsequently became permanent due to popular support. Regularly scheduled “car-free days” in Addis Ababa have inspired neighbourhood redesigns across Ethiopia (ITDP, 2019[107]).
Policy recommendations
Create attractive alternatives to private motorised vehicles to encourage the shift to sustainable transport and reduce pollution
Study after study shows that speed management, traffic calming, and physical separation of pedestrians, cyclists and micromobility users from vehicular traffic are among the most effective ways of reducing on-road injuries and deaths. This demonstrates the crucial importance of building dedicated infrastructure for active mobility and public transport to mitigate safety risks and encourage a modal shift towards less polluting travel modes.
Active travellers and people using non-active micromobility perceive dedicated infrastructure to be more comfortable – and safe – than lanes shared with vehicles in high flow areas, thus making active modes and micromobility more attractive. Shifting travel to these more sustainable modes is critical for limiting the exposure of all urban residents to toxic air pollutants.
New policies that complement dedicated infrastructure are also needed. Conflicts between active modes and micromobility are a growing concern in cities; a solid regulatory and enforcement framework is recommended to ensure micromobility vehicles are used and managed responsibly. Reducing conflicts between freight vehicles and passenger vehicles through dedicated freight loading and offloading zones is another effective policy tool for improving traffic safety.
Investing broadly in infrastructure that supports active transport, light mobility and public transport will also improve connectivity and reduce travel times. Expanding public transport networks and making stations easier to access will make opportunities across the urban area available to all, not just those who can afford a private car. The modelling results in this chapter show that even with highly ambitious transport policies, public transport travel speeds will not be competitive with private car travel speeds in all regions.
Policy makers should seek to deliver new public transport services where existing services are unavailable and improve frequency and running times across the network. Dedicated infrastructure such as bus-only lanes, transit signal priority, and queue-jump lanes can help buses move more quickly and reliably along city streets. Higher frequencies during off-peak hours can help to make public transport a viable travel option for shift workers and non-commuting trips. Proactive development of public transport infrastructure in rapidly urbanising regions is critical to avoid locking in car dependency for those on the urban periphery.
People who do not use private cars need compelling alternatives to car use to increase their access to opportunities. While car trip affordability is expected to improve in some regions by 2050, private car ownership will remain out of reach for large segments of the global population. Improving the performance and attractiveness of alternative modes such as public transport, walking, cycling and other forms of micromobility will improve equity by expanding the opportunities available to everyone.
The trip affordability modelling results show that policy measures such as expanded shared mobility incentives and integrated public transport ticketing lead to lower trip costs for driving alternatives. Land-use policies that encourage dense development around sustainable mobility hubs are an important complementary policy when making opportunities easier to access for those who do not drive.
Minimising trip costs for lower-income travellers is another approach to improving equity. Discounted transit fares for lower-income households have been shown to improve mobility and facilitate otherwise unaffordable regular healthcare trips. The upfront costs of weekly and monthly public transport passes often prevent lower-income riders from enjoying pass-based discounts.
Fare capping, which has recently been implemented in London, New York and elsewhere, eliminates this price inequity and allows everyone to choose the best fare for their travel needs. Shared mobility trips can also be cost-prohibitive for lower-income households. The ITF model results indicate that ambitious transport policies will improve the overall affordability of shared mobility trips in most regions. Nevertheless, targeted policies to make these flexible modes available to all income groups will be necessary for equitable access in the future.
Consider equity impacts when developing new transport policies, investments and programmes
Addressing women’s specific transport needs, especially concerning safety and personal security while using active and shared modes, is essential to creating liveable cities for all of society. Developers of new transport policies, investments and programmes should adopt an explicit gender lens . Active measures to boost women’s employment in the transport industry are a critical step towards social inclusivity and improved representation in decision-making processes. The ITF’s Gender Toolkit for Transport provides an interactive checklist and resources for assessing the gender inclusivity of transport projects.
A greater density of opportunities is complementary to transport performance with regard to increasing accessibility. Policy makers and planners should facilitate a wide distribution of opportunities throughout urban areas to limit the need for long-distance travel and improve accessibility in underserved neighbourhoods. To address a lack of accessibility in areas where urban amenities and social services are scarce, targeted zoning and public infrastructure investment can spur investment. New developments should integrate the planning principles of 15-minute cities and TOD to ensure that an expansion of access to jobs and social amenities accompanies urban growth.
Prioritising sustainable transport investment in previously underfunded or overburdened communities can help address historical inequities. Advancing an equitable geographic distribution of the other themes in this chapter (i.e. health and safety, accessibility and urban space) at the local level should be a top priority for future transport policy.
Equitable approaches include targeted investment in electrification to mitigate disproportionate air pollution exposure in lower-income communities and shared-mobility incentives for operators to maintain vehicle availability in neighbourhoods with few alternative mobility options. These approaches can also improve the affordability of shared modes, making opportunities more accessible to urban residents of all income levels.
Efforts to reduce the concentration of air pollutants and noise in disproportionately impacted neighbourhoods – especially in lower- and middle-income countries – are critically important for promoting equity and quality of life.
Appraisals of new public policies and infrastructure investments should measure their accessibility benefits. Many of the urban policy measures included in the High Ambition scenario are designed for implementation at the local level. Each urban area will face various design decisions and trade-offs during the planning process. Including equitable access as an explicit policy goal will guarantee that liveability considerations are integrated into decision-making processes.
Finally, while access to opportunities can be challenging to characterise in terms of monetary value, there is a growing movement to develop holistic indicators that measure accessibility benefits. Completed projects should also be evaluated on their performance to identify opportunities for further investment and to improve future estimates.
Prioritise people, not vehicles, in urban design to improve safety for all road users
Walking, micromobility and shared modes use much less space for on-road travel and vehicle storage. Incentivising a transition to space-efficient modes helps ensure more urban land is available for other uses. Policies that increase the occupancy rates of shared modes can also produce space savings by serving the same demand with fewer vehicle-kilometres of travel. Cities worldwide could reduce the static space consumption of passenger vehicles by dozens of hectares, creating the opportunity to build new green spaces and other liveability-improving community amenities.
Space consumption is not limited to passenger transport. A mixture of urban freight vehicles is needed to create logistics distribution networks that suit the urban environment. In many urban areas, large trucks and vans make deliveries on narrow, busy streets, presenting a safety hazard to other road users. Freight vehicles are also expected to contribute a significant portion of urban pollutant emissions through 2050.
Experiments with electric cargo bikes and other small vehicles should be replicated and extended in other cities around the globe to understand local challenges and opportunities. Access regulations, subsidies to offset capital costs and improved charging infrastructure could incentivise a shift towards light electric freight vehicles and unlock the associated safety, space consumption and air quality benefits.
Promoting lighter and smaller passenger vehicles would also have traffic safety benefits. Governments should consider incentives and regulations to make vehicles lighter and, therefore, safer for all road users in the event of a crash. Regulators should follow Europe’s example by incorporating measures to protect pedestrians and cyclists into vehicle safety requirements. These considerations will be especially important in the future as electric cars are often heavier than similarly-sized ICE cars.
Policy makers and planners should consider the full breadth of alternatives to the private car when planning urban areas. Vehicle sharing and ridesourcing platforms can increase accessibility for travellers by offering convenient, low-cost alternatives to private car ownership and providing access to areas that are poorly served by public transport. Shared mobility also provides modal alternatives that can make an urban area’s transport system less vulnerable to disruptions, as indicated by the modal balance results.
However, shared mobility can suffer from low utilisation and worsen traffic congestion without adequate regulation. Mileage-based fees or occupancy-based regulatory requirements could incentivise more ride pooling. Policy measures such as more robust support for carpooling and shared mobility are instrumental in achieving the reduced space consumption observed in the High Ambition scenario results.
The severity of a crash increases with travel speed, but speed limits alone are not always sufficient to instigate a behavioural change among drivers. Traffic-calming measures including narrowing travel lanes, and adding chicanes and raised crosswalks where warranted, are recommended strategies for reducing travel speeds and protecting the most vulnerable road users. Like dedicated infrastructure, traffic calming has been shown to induce a mode shift by making sustainable modes safer.
Set ambitious goals for reducing pollutant emissions and take actions to achieve them
Urban authorities can regulate urban emissions directly with LEZs in high-density urban areas. Ambitious LEZ implementation is one of the core policy measures contributing to the relative decrease in pollutants under the High Ambition scenario. When designed well, LEZs are among the most effective regulations for reducing air pollutant emissions from transport, as evidenced by examples across Asia and Europe.
Transitioning to zero-emissions public transport is another direct measure for improving air quality. Highly ambitious fleet measures effectively reduce pollutants. Yet, buses are expected to remain a significant source of toxic air pollutants such as BC, NOx, PM2.5 and SO2 in 2050. Transitioning to zero-emission vehicles will require substantial capital investment in vehicles and infrastructure.
International development and foreign aid organisations should consider allocating funds for zero-emission buses in emerging economies to ensure that the pollutant reduction benefits are widely shared. Battery-electric buses are a zero-emission option with a limited operating range. This may require adjustments to public transport routes and schedules. Policy makers should seek to learn from the experiences of other public transport agencies to smooth the transition to electric bus fleets.
References
[61] Abduljabbar, R., S. Liyanage and H. Dia (2021), “The role of micro-mobility in shaping sustainable cities: A systematic literature review”, Transportation Research Part D: Transport and Environment, Vol. 92, p. 102734, https://doi.org/10.1016/J.TRD.2021.102734.
[15] Aldred, R., J. Woodcock and A. Goodman (2021), “Major investment in active travel in Outer London: Impacts on travel behaviour, physical activity, and health”, Journal of Transport & Health, Vol. 20, p. 100958, https://doi.org/10.1016/J.JTH.2020.100958.
[58] Allam, Z. et al. (2022), “Proximity-Based Planning and the “15-Minute City”: A Sustainable Model for the City of the Future”, The Palgrave Handbook of Global Sustainability, pp. 1-20, https://doi.org/10.1007/978-3-030-38948-2_178-1.
[74] Amar, A. and C. Teelucksingh (2015), “Environmental justice, transit equity and the place for immigrants in Toronto”, Canadian Journal of Urban Research, Vol. 24/2, pp. 43-63, https://www.jstor.org/stable/26195291 (accessed on 3 October 2022).
[87] Aparicio, Á. (2018), “Equity Challenges in Major Transport Plans”, Transportation Research Procedia, Vol. 31, pp. 121-135, https://doi.org/10.1016/J.TRPRO.2018.09.054.
[92] Appelyard, D. (1980), “Liveable Streets: Protected Neighbourhoods?”, The Annals of the American Academy of Political Social Science, Vol. 451/1, pp. 106-117, https://doi.org/10.1177/000271628045100111.
[88] Bezyak, J., S. Sabella and R. Gattis (2017), “Public transportation: An investigation of barriers for people with disabilities”, Journal of Disability Policy Studies, Vol. 28/1, pp. 52-60, https://doi.org/10.1177/1044207317702070.
[69] Budnitz, H., E. Tranos and L. Chapman (2020), “Telecommuting and other trips: an English case study”, Journal of Transport Geography, Vol. 85, p. 102713, https://doi.org/10.1016/J.JTRANGEO.2020.102713.
[57] Calthorpe, P. (1993), The Next American Metropolis: Ecology, community, and the American dream, Princeton Architectural Press, New York City.
[79] Carvajal, K. and M. Alam (2018), Transport is not gender-neutral, World Bank Blogs: Transport for Development, https://blogs.worldbank.org/transport/transport-not-gender-neutral (accessed on 18 October 2022).
[95] Cervero, R. (2013), “Linking urban transport and land use in developing countries”, Journal of Transport and Land Use, Vol. 6/1, pp. 7-24, https://doi.org/10.5198/jtlu.v1.425.
[86] City of Cambridge (2019), Cycling Safety Ordinance, https://www.cambridgema.gov/streetsandtransportation/policiesordinancesandplans/cyclingsafetyordinance (accessed on 18 October 2022).
[41] Clarke, A. and M. Dornfeld (1994), Case Study No. 19 Traffic Calming, Auto-Restricted Zones and Other Traffic Management Techniques-Their Effects on Bicycling and Pedestrians, United States Federal Highway Administration, https://rosap.ntl.bts.gov/view/dot/54243 (accessed on 17 October 2022).
[46] Clean Air Asia Center (2013), Promoting Non-Motorized Transport in Asian Cities: Policymakers’ Toolbox, Clean Air Asia Center, Pasig City.
[72] Correa, F. (2022), Environmental Justice: Securing our right to a clean, healthy and sustainable environment, United Nations Development Programme, New York City, https://www.undp.org/publications/environmental-justice-securing-our-right-clean-healthy-and-sustainable-environment.
[13] Cui, H., P. Gode and S. Wappelhorst (2021), A global overview of zero-emission zones in cities and their development progress, International Council on Clean Transportation, https://theicct.org/publication/a-global-overview-of-zero-emission-zones-in-cities-and-their-development-progress (accessed on 17 October 2022).
[29] Cycle Superhighways (2019), Cycle Superhighway Bicycle Account 2019: Key figures from the cycle superhighways in the Capital Region of Denmark, Office for Cycle Superhighways, Copenhagen, https://supercykelstier.dk/wp-content/uploads/2016/03/Cycle-Superhighway-Bicycle-Account-2020.pdf.
[40] Damsere-Derry, J. et al. (2019), “Evaluation of the effectiveness of traffic calming measures on vehicle speeds and pedestrian injury severity in Ghana”, Traffic Injury Prevention, Vol. 20/3, pp. 336-342, https://doi.org/10.1080/15389588.2019.1581925.
[76] Di Ciommo, F. and Y. Shiftan (2017), “Transport equity analysis”, Transport Reviews, Vol. 37/2, pp. 139-151, https://doi.org/10.1080/01441647.2017.1278647.
[35] Edwards, M. and D. Leonard (2022), “Effects of large vehicles on pedestrian and pedalcyclist injury severity”, Journal of Safety Research, Vol. 82, pp. 275-282, https://doi.org/10.1016/J.JSR.2022.06.005.
[37] ETSC (2019), European Parliament backs new vehicle safety standards, European Transport Safety Council, https://etsc.eu/european-parliament-backs-new-vehicle-safety-standards/ (accessed on 15 February 2023).
[27] Eurostat (2021), Passenger mobility statistics: Travel mode, https://ec.europa.eu/eurostat/statistics-explained/index.php?title=Passenger_mobility_statistics#Travel_mode.
[7] Giles-Corti, B., M. Lowe and J. Arundel (2020), “Achieving the SDGs: Evaluating indicators to be used to benchmark and monitor progress towards creating healthy and sustainable cities”, Health Policy, Vol. 124/6, pp. 581-590, https://doi.org/10.1016/J.HEALTHPOL.2019.03.001.
[45] Gössling, S. and S. McRae (2022), “Subjectively safe cycling infrastructure: New insights for urban designs”, Journal of Transport Geography, Vol. 101, p. 103340, https://doi.org/10.1016/J.JTRANGEO.2022.103340.
[12] Greater London Authority (2019), Central London Ultra Low Emission Zone: Six Month Report, Greater London Authority, London, https://www.london.gov.uk/programmes-and-strategies/environment-and-climate-change/environment-publications/central-london-ulez-six-month-report (accessed on 17 October 2022).
[4] Hosking, J. et al. (2022), “Towards a global framework for transport, health and health equity”, Environment International, Vol. 169, https://doi.org/10.1016/J.ENVINT.2022.107472.
[106] ITDP (2021), Cycling and Mexico City: Better than Before, Blog: Transport Matters, https://www.itdp.org/2021/07/26/cycling-and-mexico-city-better-than-before/ (accessed on 19 October 2022).
[107] ITDP (2019), Ethiopia marks eleventh car-free day, Blog: Transport Journal, https://africa.itdp.org/ethiopia-marks-eleventh-car-free-day/ (accessed on 19 October 2022).
[103] ITDP (2012), The Life and Death of Urban Highways, Blog: Transport Journal, https://www.itdp.org/2012/03/13/the-life-and-death-of-urban-highways/.
[71] ITF (2023), Shaping Post-Covid Mobility in Cities: Summary and Conclusions, ITF Roundtable Reports, No. 190, OECD Publishing, Paris, https://doi.org/10.1787/a8bf0bdb-en.
[80] ITF (2022), Gender Analysis Toolkit for Transport, OECD Publishing, https://www.itf-oecd.org/itf-gender-analysis-toolkit-transport (accessed on 3 October 2022).
[24] ITF (2022), “Monitoring Progress in Urban Road Safety: 2022 Update”, International Transport Forum Policy Papers, No. 108, OECD Publishing, Paris, https://doi.org/10.1787/5223f587-en.
[42] ITF (2022), Road Safety in Cities: Street Design and Traffic Management Solutions, OECD Publishing, Paris, https://doi.org/10.1787/140cdf12-en.
[98] ITF (2022), Streets That Fit: Re-allocating Space for Better Cities, OECD Publishing, Paris, https://doi.org/10.1787/5593d3e2-en.
[32] ITF (2022), The Safe System Approach in Action, ITF Research Report, OECD Publishing, Paris, https://doi.org/10.1787/ad5d82f0-en.
[33] ITF (2022), The Urban Freight Space Race: Curbing the Impact of Freight Deliveries in Cities, OECD Publishing, Paris, https://doi.org/10.1787/61fdaaee-en.
[10] ITF (2021), ITF Transport Outlook 2021, OECD Publishing, Paris, https://doi.org/10.1787/16826A30-EN.
[23] ITF (2021), Road Safety Annual Report 2021: The Impact of Covid-19, OECD Publishing, Paris, https://doi.org/10.1787/9cefe972-en.
[34] ITF (2020), Best Practice for Urban Road Safety: Case Studies, OECD Publishing, Paris, https://doi.org/10.1787/03af2c0a-en.
[55] ITF (2019), “Benchmarking Accessibility in Cities: Measuring the Impact of Proximity and Transport Performance”, International Transport Forum Policy Papers, No. 68, OECD Publishing, Paris, https://doi.org/10.1787/4b1f722b-en.
[50] ITF (2019), Improving Transport Planning and Investment Through the Use of Accessibility Indicators, OECD Publishing, Paris, https://doi.org/10.1787/46ddbcae-en.
[78] ITF (2019), Transport Connectivity: A Gender Perspective, OECD Publishing, Paris, http://www.itf-oecd.org (accessed on 26 January 2021).
[38] ITF (2017), “Lightening Up: How Less Heavy Vehicles Can Help Cut CO2 Emissions”, International Transport Forum Policy Papers, No. 40, OECD Publishing, Paris, https://doi.org/10.1787/ecf5b956-en.
[54] ITF (n.d.), How accessible is your city?, https://www.itf-oecd.org/urban-access-framework.
[99] ITF (forthcoming), New Mobility Outlook, OECD Publishing, Paris.
[67] Karam, A., K. Reinau and C. Østergaard (2021), “Horizontal collaboration in the freight transport sector: barrier and decision-making frameworks”, European Transport Research Review, Vol. 13, https://etrr.springeropen.com/articles/10.1186/s12544-021-00512-3.
[105] Kasprzyk, M. et al. (2022), “Technical solutions and benefits of introducing rain gardens – Gdańsk case study”, Science of The Total Environment, Vol. 835, p. 155487, https://doi.org/10.1016/J.SCITOTENV.2022.155487.
[104] Khalaj, F. et al. (2020), “Why are cities removing their freeways? A systematic review of the literature”, Transport Reviews, Vol. 40/5, pp. 557-580, https://doi.org/10.1080/01441647.2020.1743919.
[96] Labib, S., H. Mohiuddin and S. Shakil (2013), “Transport Sustainability of Dhaka: A Measure of Ecological Footprint and Means for Sustainable Transportation System”, Journal of Bangladesh Institute of Planners, Vol. 6, pp. 137-147, https://papers.ssrn.com/abstract=2514806 (accessed on 14 October 2022).
[49] Lavasani et al (2016), “Market penetration model for autonomous vehicles on the basis of earlier technology adoption experience”, Transport Research Record, Vol. 2597, https://doi.org/10.3141/2597-09.
[97] Lazarus, J. et al. (2021), “To Pool or Not to Pool? Understanding opportunities, challenges, and equity considerations to expanding the market for pooling”, Transportation Research Part A: Policy and Practice, Vol. 148, pp. 199-222, https://doi.org/10.1016/J.TRA.2020.10.007.
[84] Litman, T. (2022), Evaluating Accessibility for Transport Planning: Measuring People’s Ability to Reach Desired Services and Activities, Victoria Transport Policy Institute, Victoria, https://trid.trb.org/view/859513.
[63] Loo, B. and A. Siiba (2019), “Active transport in Africa and beyond: towards a strategic framework”, Transport Reviews, Vol. 39/2, pp. 181-203, https://doi.org/10.1080/01441647.2018.144288.
[73] Louis, P. and A. Skinner (2021), Environmental Justice Finally Legitimized in Massachusetts, Public Health Post, https://www.publichealthpost.org/viewpoints/environmental-justice-massachusetts/ (accessed on 3 October 2022).
[6] Lowe, M. et al. (2022), “City planning policies to support health and sustainability: an international comparison of policy indicators for 25 cities”, The Lancet Global Health, Vol. 10/6, pp. e882-e894, https://doi.org/10.1016/S2214-109X(22)00069-9/ATTACHMENT/39BAD32B-D58E-4D6E-8700-F41915DB6CDC/MMC1.PDF.
[3] Lowe, M. et al. (2015), “Planning Healthy, Liveable and Sustainable Cities: How Can Indicators Inform Policy?”, Urban Policy and Research, Vol. 33/2, pp. 131-144, https://doi.org/10.1080/08111146.2014.1002606.
[60] Lung-Amam, W., R. Pendall and E. Knaap (2019), “Mi Casa no es Su Casa: The Fight for Equitable Transit-Oriented Development in an Inner-Ring Suburb”, Journal of Planning Education and Research, Vol. 39/4, pp. 442-455, https://doi.org/10.1177/0739456X19878248.
[18] Mackett, R. and R. Thoreau (2015), “Transport, social exclusion and health”, Journal of Transport & Health, Vol. 2/4, pp. 610 - 617, https://doi.org/10.1016/j.jth.2015.07.006.
[101] Marks, G. (2021), “Outdoor dining has been a Covid bright spot. Let’s make it permanent”, The Guardian, https://www.theguardian.com/business/2021/jan/10/coronavirus-covid-outdoor-dining-restaurants (accessed on 3 October 2022).
[48] McDonald, N. and Q. Yuan (2021), “Freight Loading Space Provision: Evidence from the US”, Journal of Urban Planning and Development, Vol. 147/2, p. 04021015, https://doi.org/10.1061/(ASCE)UP.1943-5444.0000688.
[102] Mesmer, P. (2014), “Seoul demolishes its urban expressways as city planners opt for greener schemes”, The Guardian, https://www.theguardian.com/world/2014/mar/13/seoul-south-korea-expressway-demolished (accessed on 3 October 2022).
[94] Meyer, J. and J. Gómez-Ibáñez (1981), Autos, Transit, and Cities, Harvard University Press, Cambridge, MA, https://doi.org/10.4159/HARVARD.9780674421103.
[52] Morris, J., P. Dumble and M. Wigan (1979), “Accessibility indicators for transport planning”, Transportation Research Part A: General, Vol. 13/2, pp. 91-109, https://doi.org/10.1016/0191-2607(79)90012-8.
[21] Muller, N. and R. Mendelsohn (2007), “Measuring the damages of air pollution in the United States”, Journal of Environmental Economics and Management, Vol. 54/1, pp. 1-14, https://doi.org/10.1016/J.JEEM.2006.12.002.
[19] Nadrian, H. et al. (2019), “’I am sick and tired of this congestion’: Perceptions of Sanandaj inhabitants on the family mental health impacts of urban traffic jam”, Journal of Transport & Health, Vol. 14, https://doi.org/10.1016/j.jth.2019.100587.
[28] OECD (2022), Guidebook on Best Practices in Public Health, OECD Publishing, Paris, https://doi.org/10.1787/4f4913dd-en.
[83] OECD (2022), Infrastructure investment (indicator), https://doi.org/10.1787/b06ce3ad-en (accessed on 26 October 2022).
[25] OECD (2021), Health at a Glance 2021: OECD Indicators, OECD Publishing, Paris, https://doi.org/10.1787/ae3016b9-en.
[56] OECD (2020), Improving Transport Planning for Accessible Cities, OECD Publishing, Paris, https://doi.org/10.1787/fcb2eae0-en.
[14] OECD (2020), Non-exhaust Particulate Emissions from Road Transport: An Ignored Environmental Policy Challenge, OECD Publishing, Paris, https://doi.org/10.1787/4a4dc6ca-en.
[26] OECD (2019), The Heavy Burden of Obesity: The Economics of Prevention, OECD Health Policy Studies, OECD Publishing, Paris, https://doi.org/10.1787/67450d67-en.
[89] OECD (2015), Ageing in Cities, OECD Publishing, Paris, https://doi.org/10.1787/9789264231160-en.
[31] OECD (forthcoming), Promoting Healthy Environments: Best Practices in Public Health, OECD Publishing, Paris.
[16] OECD/ITF (2013), Cycling, Health and Safety, ITF Research Report, OECD Publishing/International Transport Forum, Paris, https://doi.org/10.1787/9789282105955-en.
[100] O’Sullivan, F. (2021), “Paris Will Keep Its Covid-Era Cafe Terraces”, Bloomberg, https://www.bloomberg.com/news/articles/2021-06-15/paris-will-keep-its-covid-era-cafe-terraces (accessed on 19 October 2022).
[2] Paul, A. and J. Sen (2020), “A critical review of liveability approaches and their dimensions”, Geoforum, Vol. 117, pp. 90-92, https://doi.org/10.1016/j.geoforum.2020.09.008.
[82] Pereira, R. and A. Karner (2021), “Transportation Equity”, International Encyclopedia of Transportation, pp. 271-277, https://doi.org/10.1016/B978-0-08-102671-7.10053-3.
[75] Perry, K. (2013), Black Women against the Land Grab: The Fight for Racial Justice in Brazil, University of Minnesota Press, Minneapolis, MN, https://doi.org/10.5749/MINNESOTA/9780816683239.001.0001.
[59] Rahman, M., F. Ashik and M. Mouli (2022), “Investigating spatial accessibility to urban facility outcome of transit-oriented development in Dhaka”, Transportation Research Interdisciplinary Perspectives, Vol. 14, p. 100607, https://doi.org/10.1016/J.TRIP.2022.100607.
[65] Rahman, M. et al. (2023), “Active transportation and the built-environment of a mid-size global south city”, Sustainable Cities and Society, Vol. 89, https://doi.org/10.1016/j.scs.2022.104329.
[68] Ramani, A. and N. Bloom (2021), “The Donut Effect of Covid-19 on Cities”, NBER Working Papers, No. 28876, https://doi.org/10.3386/w28876.
[44] Reynolds, C. et al. (2009), “The impact of transportation infrastructure on bicycling injuries and crashes: A review of the literature”, Environmental Health: A Global Access Science Source, Vol. 8/1, pp. 1-19, https://doi.org/10.1186/1476-069X-8-47/TABLES/3.
[77] Rosenblum, J. (2020), Expanding access to the city: how public transit fare policy shapes travel decision making and behavior of low-income riders, Massachusetts Institute of Technology, https://dspace.mit.edu/handle/1721.1/127617 (accessed on 18 October 2022).
[11] Sclar, R. et al. (2019), Barriers to Adopting Electric Buses, World Resources Institute, Washington, DC, https://www.wri.org/research/barriers-adopting-electric-buses.
[64] Sharmeen, F., B. Ghosh and I. Mateo-Babiano (2021), “Policy, users and discourses: Examples from bikeshare programs in (Kolkata) India and (Manila) Philippines”, Journal of Transport Geography, Vol. 90, https://doi.org/10.1016/j.jtrangeo.2020.102898.
[62] Sohail, M., D. Maunder and S. Cavill (2006), “Effective regulation for sustainable public transport in developing countries”, Transport Policy, Vol. 13/3, pp. 177-190, https://doi.org/10.1016/j.tranpol.2005.11.004.
[5] Tolfo, G. and B. Doucet (2022), “Livability for whom?: Planning for livability and the gentrification of memory in Vancouver”, Cities, Vol. 123, https://doi.org/10.1016/j.cities.2022.103564.
[47] Ton, D. et al. (2019), “Cycling or walking? Determinants of mode choice in the Netherlands”, Transportation Research Part A: Policy and Practice, Vol. 123, pp. 7-23, https://doi.org/10.1016/J.TRA.2018.08.023.
[90] UN DESA (2022), World Population Prospects 2022, Online Edition, https://www.un.org/development/desa/pd/sites/www.un.org.development.desa.pd/files/wpp2022_summary_of_results.pdf.
[93] UN-Habitat (2013), Streets as Public Spaces and Drivers of Urban Prosperity, United Nations Human Settlements Programme, Nairobi, https://unhabitat.org/streets-as-public-spaces-and-drivers-of-urban-prosperity.
[1] United Nations (2014), Liveable Cities Key to Sustainable Development, Secretary-General Stresses in Message for International Day, United Nations, https://press.un.org/en/2014/sgsm16293.doc.htm (accessed on 3 October 2022).
[66] Vanovermeire, C. et al. (2014), “Horizontal logistics collaboration: decreasing costs through flexibility and an adequate cost allocation strategy”, International Journal of Logistics Research and Applications, Vol. 17/4, pp. 339-355, https://doi.org/10.1080/13675567.2013.865719.
[20] Veber, T. et al. (2022), “Health impact assessment of transportation noise in two Estonian cities”, Environmental Research, Vol. 204, Part C, https://doi.org/10.1016/j.envres.2021.112319.
[30] Vélib’ (2022), Vélib’ en chiffres [Vélib’ in numbers], Vélib’ Métropole, Paris, https://blog.velib-metropole.fr/2022/03/01/velib-en-chiffres/ (accessed on 18 May 2022).
[85] Venter, C., A. Mahendra and D. Hidalgo (2019), From Mobility to Access for All: Expanding Urban Transportation Choices in the Global South, https://www.sipotra.it/wp-content/uploads/2019/05/From-Mobility-to-Access-for-All-Expanding-Urban-Transportation-Choices-in-the-Global-South.pdf.
[81] Verlinghieri, E. and T. Schwanen (2020), “Transport and mobility justice: Evolving discussions”, Journal of Transport Geography, Vol. 87, p. 102798, https://doi.org/10.1016/J.JTRANGEO.2020.102798.
[51] Weibull, J. (1976), “An axiomatic approach to the measurement of accessibility”, Regional Science and Urban Economics, Vol. 6/4, pp. 357-379, https://doi.org/10.1016/0166-0462(76)90031-4.
[43] Welle, B. et al. (2015), Cities Safer by Design, World Resources Institute, Washington, DC, https://www.wri.org/research/cities-safer-design.
[17] Whitley, R. and M. Prince (2005), “Fear of Crime, mobility and mental health in inner-city London, UK”, Social Science & Medicine, Vol. 61/8, pp. 1678 - 1688, https://doi.org/10.1016/j.socscimed.2005.03.044.
[22] WHO (2022), Road traffic injuries, https://www.who.int/news-room/fact-sheets/detail/road-traffic-injuries (accessed on 3 October 2022).
[8] WHO (2021), Fact Sheet: Ambient (Outdoor) Air Pollution, World Health Organization, https://www.who.int/news-room/fact-sheets/detail/ambient-(outdoor)-air-quality-and-health (accessed on 3 October 2022).
[39] Wilmot, C. and M. Khanal (2010), “Effect of Speed limits on speed and safety: A review”, Transport Reviews, Vol. 19/4, pp. 315-329, https://doi.org/10.1080/014416499295420.
[70] Wöhner, F. (2022), “Work flexibly, travel less? The impact of telework and flextime on mobility behavior in Switzerland”, Journal of Transport Geography, Vol. 102, p. 103390, https://doi.org/10.1016/J.JTRANGEO.2022.103390.
[9] World Bank (2022), World Development Indicators - Country Income Classifications, https://datahelpdesk.worldbank.org/knowledgebase/articles/378834-how-does-the-world-bank-classify-countries (accessed on 7 November 2022).
[53] Wu, H. et al. (2021), “Urban access across the globe: an international comparison of different transport modes”, npj Urban Sustainability 2021 1:1, Vol. 1/1, pp. 1-9, https://doi.org/10.1038/s42949-021-00020-2.
[91] Yung, E., S. Conejos and E. Chan (2016), “Public open spaces planning for the elderly: The case of dense urban renewal districts in Hong Kong”, Land Use Policy, Vol. 59, pp. 1-11, https://doi.org/10.1016/j.landusepol.2016.08.022.
[36] Zipper, D. (2022), “A New Way to Curb the Rise of Oversized Pickups and SUVs - Bloomberg”, Bloomberg, https://www.bloomberg.com/news/articles/2022-05-26/a-new-way-to-curb-the-rise-of-oversized-pickups-and-suvs (accessed on 17 October 2022).