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Beat the Traffic: Increasing Public Support for Congestion Relief Policies in Latin American Cities

Posted on May 26, 2021
Traffic congestion on a highway

By: Xize Wang, Assistant Professor
Department of Real Estate, National University of Singapore

Traffic congestion imposes huge economic and health costs on urban residents. In São Paulo and Mexico City, drivers spend more than 50 hours a year in peak traffic congestion. In Bogotá, the cost of congestion is 1% of the daily earned wage of workers. Traffic congestion is also a major cause of air pollution, which contributes to chronic respiratory diseases that account for 3.9 million deaths per year.

To fight congestion, policy makers tend to consider two major types of policies: charging for road use and driving restrictions. Charging drivers for using the road is a market-based mechanism that commonly involves imposing a fee for entering highways or downtown areas (for instance, Singapore’s ERP system). Driving restrictions limit the circulation of vehicles either in the entire city or certain areas, normally by the last digit of one’s license plate, depending on the day of the week and time of day. Bogotá, La Paz, Medellin, São Paulo, and Quito are Latin American cities that have implemented driving restrictions due to traffic congestion concerns.

Left: Singapore's road pricing policy. Right: Bogata's driving restrictions policy

The level of public support for these congestion relief policies determines their success. New research from SALURBAL, published in Transportation Research Part A: Policy and Practice identified the factors associated with the level of public support towards road pricing and driving restrictions in 11 Latin American cities. The dataset of this study comes from a survey conducted by CAF – The Development Bank of Latin America. The findings of this study can help policy makers to develop effective strategies to promote the public’s acceptance of various types of congestion relief policies.

This study includes data from 11 cities: Mexico City, Panama City, Caracas, Quito, Bogata, Lima, Fortazela, Sao Paulo, La Paz, Montevideo, Buenos Aires

Opinions vary, but driving restrictions are more popular than road pricing

Driving restrictions are more popular than road pricing in the 11 cities. Residents of La Paz, Bolivia had the highest support for any congestion relief policy (77.9% of respondents). In contrast, only 37.9% of the respondents in Caracas, Venezuela supported congestion relief policies, the lowest of all cities.

Chart showing the proportion of survey respondents who supported road pricing, driving restrictions, or either policy.

Policy makers should highlight the health benefits of fighting traffic congestion

The study identified factors associated with support for road pricing, driving restrictions and either of these two congestion relief policies. In addition to personal transportation factors of the survey respondents (vehicle ownership, car use, and personal traffic delay), the study also found that environmental health factors are associated with residents’ support for congestion relief policies.

Specifically, having a child with recent respiratory disease is associated with 5.9% higher likelihood of supporting congestion relief policies, and living in a city with 1μg/m3 higher PM 2.5 (particulate matter, a type of air pollution) concentration is associated with 1.5% higher likelihood of support for the policies. When planning for congestion relief policies, policy makers should highlight that the proposed policy not only reduces the level of traffic congestion, they should also highlight that these policies will help to make the air cleaner and children healthier.

Caregivers of children who suffered from a recent respiratory disease are 5.9% more likely to support congestion relief policies.

High urban inequalities increase support for driving restrictions but not road pricing

Aspects of city economies, especially income inequality, are associated with support towards market-based vs. command-and-control congestion relief policies. Specifically, the study found that an 0.1 increase of a city’s Gini coefficient (a measure of income inequality, where higher values indicate higher inequality) is associated with a 7.2% higher likelihood of supporting driving restrictions but not for road pricing. This finding indicates the importance of considering income inequality issues if a decision-makers are proposing road pricing policies, as lower-income residents may consider road pricing as an opportunity for the wealthy to buy more exclusive access to the city’s road systems. One way to address this issue is to ensure that the money collected by road pricing is used to build and improve high quality, low-cost public transportation systems that will benefit low-income populations.

Harness the power of “pilot programs”

Finally, the study found that living in a city already having driving restrictions is associated with 14.2% higher likelihood of support either congestion relief policy. This shows the “status quo bias,” where city residents may be reluctant towards congestion relief policies because they do not really know what benefits the proposed policies could bring about, while those previously exposed to these policies feel more open to supporting them. Implementing small “pilot programs” could help city residents to realize the benefits of such programs and be more likely to support them.

Policy makers should consider all factors influencing support for congestion relief policies

In summary, many factors are related to public support of road pricing and driving restriction policies. Policy makers should make an effort to take all of these factors into account when they propose such policies.

This study shows that policy makers can improve public acceptance of congestion relief policies in Latin America by:

  • Explicitly seeking to mitigate the costs of policies on individuals by investing in substitutes like public transportation,
  • Highlighting the environmental and health benefits of these policies,
  • Implementing temporary pilot programs to help the public see the benefits of these programs and build support, and
  • Taking into account city-specific conditions related to income inequality that may influence public support for these policies, especially driving restrictions.
Posted in Sustainable Development, Public Policies, Mobility and Emissions Control