Public transportation systems

Evidence Rating  
Evidence rating: Scientifically Supported

Strategies with this rating are most likely to make a difference. These strategies have been tested in many robust studies with consistently positive results.

Disparity Rating  
Disparity rating: Potential for mixed impact on disparities

Strategies with this rating could increase and decrease disparities between subgroups. Rating is suggested by evidence or expert opinion.

Health Factors  
Date last updated

Public transportation systems include buses, trains, trams, trolleybuses, ferries, or rapid transit (e.g., light rail transit (LRT), bus rapid transit (BRT), or heavy rail such as subways) that are available for use by the public and run on a scheduled timetable. Transportation systems are most common in urban areas and are often supported by federal and municipal funds1.

What could this strategy improve?

Expected Benefits

Our evidence rating is based on the likelihood of achieving these outcomes:

  • Increased access to public transit

  • Increased use of public transit

Potential Benefits

Our evidence rating is not based on these outcomes, but these benefits may also be possible:

  • Increased physical activity

  • Reduced vehicle miles traveled

  • Reduced emissions

What does the research say about effectiveness?

There is strong evidence that introducing or expanding public transportation systems in urban areas increases access to and use of public transit, especially in dense, centralized cities2, 3, 4, 5, 6, 7.

Introducing or expanding public transportation systems can increase physical activity8, 9, 10, particularly when implemented as part of a multi-component land use approach11, and transit users appear to have higher levels of physical activity than their peers12, 13. Light rail transit (LRT) appears to increase physical activity9, 10, particularly for new riders9, and may reduce body mass index (BMI) and decrease the likelihood of obesity10. Opening a new LRT line may decrease the number of no-show appointments at local clinics, particularly for patients receiving Medicaid and for patients residing near stations who receive care at clinics near other stations14.

Reducing fares and increasing the frequency and quality of transit service appear to be the most effective ways to increase use of existing public transit systems15, 16. Frequent, reliable service with few transfers may also make public transit more appealing to drivers17 and may increase rider satisfaction18. Introducing new rail lines in urban areas can increase transit use in cities where many commuters drive to a central business district, and significantly reduce trip time for commuters and other travelers3, 4. Real-time bus tracking may modestly increase ridership and revenue2, and improve rider satisfaction2, 19. Distance-based fare reductions may increase ridership among those who often use public transit to travel shorter distances20. In areas with existing high levels of ridership, when stations and stops for multiple types of transit, such as LRT, metros, or buses, either overlap or are nearby, it may support new ridership and users may substitute one type for another, reducing congestion on the busiest routes21.

Public transportation systems produce significantly lower emissions per passenger mile than private vehicles, especially when operating with full passenger loads22, 23. These systems can lower their operational emissions by introducing LRT, which operates on electricity, and update buses and train locomotives to newer models that use cleaner fuel sources24. Introducing or expanding an LRT system can reduce vehicle miles traveled (VMT) and greenhouse gas emissions among households living within half a mile of an LRT station4. Emissions reductions for LRT and bus rail transit (BRT) systems can be affected by local regulations and component technologies25, as well as seasonal ridership changes in areas with large rapid demographic shifts, like college towns24.

New public transportation systems may encourage business development and revitalization, even in historically car-centric cities, though initial effects may diminish over time26. Opening new transit stations may lead to changes in the pedestrian infrastructure of the surrounding area, especially cross streets and sidewalks immediately around stations, improving accessibility27. Increases in public transit use may increase multi-family housing development near suburban rail stations28, and model-based research suggests that subsidizing and investing in public transportation infrastructure can also limit urban sprawl, reduce car use, and promote active transit29.

City planners need to anticipate the potential for gentrification and consider strategies to preserve affordable housing, such as expanding housing opportunities in a mixed-use environment30. While some studies have found no impact of public transportation on nearby property values and rents31, 32, 33, 34, several others suggest that LRT may lead to gentrification as individuals with higher incomes move near stations35, 36, driving up rents35, 36 and property values34, 35, 36 and displacing existing residents with lower incomes35, 36, 37. These gentrification effects may begin once a new system or line is announced, well before its construction30. Some studies find that, over the long-term, residents of neighborhoods with LRT access may be more likely to have greater discretionary income38, be employed full time, and not experience significant rent increases31, but it is unclear if these are gentrification effects38. Bus transit is less likely to increase rent around stations and stops35. However, a Virginia-based study of a small city adding a light rail system found that property values near new stations decreased, suggesting city planners in less populous cities should carefully consider where, when, and how public transportation systems are implemented39.

How could this strategy advance health equity? This strategy is rated potential for mixed impact on disparities: supported by some evidence.

There is some evidence that public transportation systems can have mixed effects on disparities in access to and use of public transit. People with low incomes, people of color, older adults, those too young to drive, and people with disabilities are more likely to use public transportation, especially to access employment53, 54. However, available evidence suggests impacts vary based on the type of public transit available and where it is located55.

Light rail transit (LRT) systems appear to be more likely than other types of public transit to contribute to the displacement of people with low incomes, and often people of color, due to neighborhood gentrification35, 55, 56, 57, and increased rents37. Displacement of residents with low incomes and people of color to other neighborhoods with fewer amenities and worse transit accessibility may increase inequities55. Bus transit is more likely to benefit people with low incomes without increasing rent around stations and stops35. Experts suggest that explicitly centering equity in implementation of public transportation systems may limit gentrification38 and income-based social stratification and increase quality of life for residents with lower incomes58 while building more compact, active communities38, 58.

Overall, additional research is needed to understand the effects of public transportation systems on people with low incomes and people of color38, 58, including what roles zoning, neighborhood design, and affordability may play in preventing transit-induced gentrification59.

What is the relevant historical background?

Public transportation systems in the U.S. have been shaped by many factors, including car ownership, residential living patterns, federal funding, and the mass construction of interstate highways. Ultimately, the growth and sprawl of cities in the U.S. was largely driven by discriminatory housing policies and car-centric urban planning which often prevents provision of equitable, consistent, and reliable public transit service60.

In the 19th century and early 20th century, streetcars helped define residential and commercial areas in cities59. Then, beginning in the 1950s, white families left cities for suburban neighborhoods and investments in public transit declined60. The creation of the modern interstate highway system fed into a dependence on private automobiles, leading to low density suburban development, urban sprawl, and further decline in urban transit systems. Highways bypassed rural towns and at the same time cut through and destroyed low income and Black neighborhoods in cities59, while car-centric urban planning reduced access to public transportation options, increased residential segregation, and further embedded health disparities61.

In recent years, transit-driven gentrification in urban, low income, and frequently Black neighborhoods has driven out long-term residents, and displaced and relocated them to under-resourced urban areas known as transit deserts, which lack enough public transportation options to meet local demand59.

Equity Considerations
  • Who has poor access to transit in your community? How can planners engage local community members to learn about the challenges they experience and what changes to existing services could improve their access?
  • How would a new system, or the introduction of a new line, impact access for current residents? Which strategies and partnerships are necessary to protect current residents from possible displacement or gentrification?
  • What opportunities are there to connect transit service areas with affordable housing, Low Income Housing Tax Credits (LIHTC), inclusionary zoning, or other housing programs? Who can you partner with to increase these opportunities?
  • How have historic patterns of zoning, traffic designs, and other built environment features contributed to local challenges to adding public transportation options, such as accessibility and pedestrian safety? How has power (i.e. money, knowledge, interpersonal relationships, etc.) shaped these historic patterns, and how will it influence future decision-making?
Implementation Examples

U.S. transit systems were used for 9.9 billion passenger trips in 2019; buses accounted for roughly half of all passenger trips40. In 2019, 55% of U.S. households reported having access to public transportation40.

Many municipalities have introduced or expanded public transportation systems. New York, New York41; San Francisco, California42; Boston, Massachusetts43; Washington, D.C.44; Philadelphia, Pennsylvania45; Chicago, Illinois46; Seattle, Washington47; Baltimore, Maryland48; Los Angeles, California49; and Portland, Oregon50 are examples of cities with heavily used, multi-faceted systems.

Portland, one of the most walkable cities in the U.S., centered equity in their public transit system which led to policies such as tax abatement for building multi-family housing close to transit stations51. Similarly, Seattle, one of the busiest transit corridors in the U.S., is focused on connecting entire regions with different types of public transit, including light rail transit (LRT) systems and more frequent, reliable bus services as a part of their transportation equity program52.

Implementation Resources

Resources with a focus on equity.

CDC-PA Transportation - Centers for Disease Control and Prevention (CDC). What’s your role? Transportation.

ULI Building healthy places - Urban Land Institute (ULI) Building Healthy Places Initiative. Building healthy places toolkit: Strategies for enhancing health in the built environment.

APTA-Transit facts - American Public Transportation Association (APTA). Where Public Transportation Goes Community Grows. Transit facts at a glance.

HPbD - Healthy Places by Design (HPbD). Advances community-led action and proven, place-based strategies to ensure health and wellbeing for all.

TDM-Public transit - TDM Encyclopedia. Public transit improvements. Victoria Transport Policy Institute.

APTA-Resources - American Public Transportation Association (APTA). Research and technical resources.

SRTSNP-Safe routes to healthy foods - Safe Routes to School National Partnership (SRTSNP). Healthy communities: Safe routes to healthy foods.

LHS - Local Housing Solutions (LHS). To enhance local affordability and foster inclusive communities. New York University, Furman Center and Abt Associates, Inc.

Urban-Stacy 2022a - Stacy CP, Ramos K, Harvey D, et al. Recommendations for increasing transportation equity in South Dallas. Washington, D.C.: Urban Institute; 2022.

Project Drawdown-PT - Project Drawdown. Climate solutions: Public transit.


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1 US DOT-FTA - U.S. Department of Transportation (U.S. DOT), Federal Transit Administration (FTA). About FTA: Improving public transportation for America’s communities.

2 Brakewood 2015 - Brakewood C, Macfarlane GS, Watkins K. The impact of real-time information on bus ridership in New York City. Transportation Research Part C: Emerging Technologies. 2015;53:59-75.

3 Baum-Snow 2005 - Baum-Snow N, Kahn ME. Effects of urban rail transit expansions: Evidence from sixteen cities, 1970–2000. Brookings-Wharton Papers on Urban Affairs. 2005;(6):147.

4 Boarnet 2013 - Boarnet MG, Hong A, Lee J, et al. The exposition light rail line study: A before-and-after study of the impact of new light rail transit service. University of Southern California. 2013.

5 Cao 2014 - Cao X, Schoner J. The influence of light rail transit on transit use: An exploration of station area residents along the Hiawatha line in Minneapolis. Transportation Research Part A: Policy and Practice. 2014;59:134-143.

6 TRB-Callaghan 2007 - Callaghan L, Vincent W. Preliminary evaluation of metro orange line bus rapid transit project. Transportation Research Record: Journal of the Transportation Research Board. 2007;2034(1):37-44.

7 TRB-Polzin 2003 - Polzin SE, Page OA. Ridership trends of new start rail projects. Transportation Research Circular E-C058: 9th National Light Rail Transit Conference. Transportation Research Board (TRB); 2003.

8 Sener 2016 - Sener IN, Lee RJ, Elgart Z. Potential health implications and health cost reductions of transit-induced physical activity. Journal of Transport & Health. 2016;3(2):133-140.

9 Brown 2015a - Brown BB, Werner CM, Tribby CP, Miller HJ, Smith KR. Transit use, physical activity, and body mass index changes: Objective measures associated with complete street light-rail construction. American Journal of Public Health. 2015;105(7):1468-1474.

10 MacDonald 2010 - MacDonald JM, Stokes RJ, Cohen DA, Kofner A, Ridgeway GK. The effect of light rail transit on body mass index and physical activity. American Journal of Preventive Medicine. 2010;39(2):105-12.

11 CG-Physical activity - The Guide to Community Preventive Services (The Community Guide). Physical activity.

12 Saelens 2014 - Saelens BE, Vernez Moudon A, Kang B, Hurvitz PM, Zhou C. Relation between higher physical activity and public transit use. American Journal of Public Health. 2014;104(5):854-859.

13 Wener 2007 - Wener RE, Evans GW. A morning stroll: Levels of physical activity in car and mass transit commuting. Environment and Behavior. 2007;39(1):62-74.

14 Smith 2022 - Smith LB, Yang Z, Golberstein E, et al. The effect of a public transportation expansion on no-show appointments. Health Services Research. 2022;57(3):472-481.

15 Taylor 2013 - Taylor JC, Johnson RK. Farm to school as a strategy to increase children's fruit and vegetable consumption in the United States: Research and recommendations. Nutrition Bulletin. 2013;38(1):70-79.

16 Taylor 2009 - Taylor BD, Miller D, Iseki H, Fink C. Nature and/or nurture? Analyzing the determinants of transit ridership across U.S. urbanized areas. Transportation Research Part A: Policy and Practice. 2009;43(1):60-77.

17 Chakrabarti 2017 - Chakrabarti S. How can public transit get people out of their cars? An analysis of transit mode choice for commute trips in Los Angeles. Transport Policy. 2017;54:80-89.

18 Wan 2016 - Wan D, Kamga C, Liu J, Sugiura A, Beaton EB. Rider perception of a “light” Bus Rapid Transit system - The New York City Select Bus Service. Transport Policy. 2016;49:41-55.

19 Brakewood 2014 - Brakewood C, Barbeau S, Watkins K. An experiment evaluating the impacts of real-time transit information on bus riders in Tampa, Florida. Transportation Research Part A: Policy and Practice. 2014;69:409-422.

20 Farber 2014 - Farber S, Bartholomew K, Li X, Páez A, Nurul Habib KM. Assessing social equity in distance based transit fares using a model of travel behavior. Transportation Research Part A: Policy and Practice. 2014;67:291-303.

21 Jiao 2022 - Jiao J, Chen Y. Is the relationship between bus and light rail transit a competition substitution or a congestion substitution? An empirical study in Seattle. Public Transport. 2022.

22 US DOT-FTA Transit and climate - U.S. Department of Transportation (U.S. DOT), Federal Transit Administration (FTA). Public transportation's role in responding to climate change. 2010.

23 Project Drawdown-PT - Project Drawdown. Climate solutions: Public transit.

24 Mendoza 2019 - Mendoza DL, Buchert MP, Lin JC. Modeling net effects of transit operations on vehicle miles traveled, fuel consumption, carbon dioxide, and criteria air pollutant emissions in a mid-size U.S. metro area: Findings from Salt Lake City, UT. Environmental Research Communications. 2019;1(9):091002.

25 TRB-Puchalsky 2005 - Puchalsky CM. Comparison of emissions from light rail transit and bus rapid transit. Transportation Research Record: Journal of the Transportation Research Board. 2005;1927(1):31-37.

26 Credit 2018 - Credit K. Transit-oriented economic development: The impact of light rail on new business starts in the Phoenix, AZ Region, USA. Urban Studies. 2018;55(13):2838-2862.

27 Agustini 2022 - Agustini KAV, West SE. Redevelopment along arterial streets: The effects of light rail on land use change. Real Estate Economics. 2022.

28 Dong 2016 - Dong H. If you build rail transit in suburbs, will development come? Journal of the American Planning Association. 2016;82(4):316-326.

29 Su 2008 - Su Q, DeSalvo JS. The effect of transportation subsidies on urban sprawl. Journal of Regional Science. 2008;48(3):567-594.

30 Chava 2021 - Chava J, Renne JL. Transit-induced gentrification or vice versa? A study of neighborhoods around light rail stations from 1970–2010. Journal of the American Planning Association. 2022;88(1):44-54.

31 Kim 2021c - Kim K, Park K, Nelson AC. Impacts of light rail transit on labor participation and housing affordability in the U.S.: Longitudinal analysis using propensity score matching. Transportation Research Record. 2021;2675(12):419-431.

32 Baker 2019 - Baker DM, Lee B. How does light rail transit (LRT) impact gentrification? Evidence from fourteen U.S. urbanized areas. Journal of Planning Education and Research. 2019;39(1):35-49.

33 Ransom 2018 - Ransom MR. The effect of light rail transit service on nearby property values: Quasi-experimental evidence from Seattle. Journal of Transport and Land Use. 2018;11(1):387-404.

34 Pilgram 2018 - Pilgram CA, West SE. Fading premiums: The effect of light rail on residential property values in Minneapolis, Minnesota. Regional Science and Urban Economics. 2018;69:1-10.

35 Tyndall 2021 - Tyndall J. The local labour market effects of light rail transit. Journal of Urban Economics. 2021;124:103350.

36 MAPC-Displacement - Metropolitan Area Planning Council (MAPC) Massachusetts. Dimensions of Displacement: Baseline data for managing neighborhood change in Somerville's Green Line Corridor. 2014.

37 Bardaka 2018 - Bardaka E, Delgado MS, Florax RJGM. Causal identification of transit-induced gentrification and spatial spillover effects: The case of the Denver light rail. Journal of Transport Geography. 2018;71:15-31.

38 Baker 2020b - Baker DM, Kim S. What remains? The influence of light rail transit on discretionary income. Journal of Transport Geography. 2020;85:102709.

39 Wagner 2017a - Wagner GA, Komarek T, Martin J. Is the light rail “tide” lifting property values? Evidence from Hampton Roads, VA. Regional Science and Urban Economics. 2017;65:25-37.

40 ASCE-2021 Report card - American Society of Civil Engineers (ASCE). 2021 Infrastructure report card: Transit report.

41 NYC MTA - New York City Metropolitan Transportation Authority (NYC MTA). Transit information.

42 SF MTA - San Francisco Municipal Transportation Agency (SF MTA). Transportation choices.

43 MBTA - Massachusetts Bay Transportation Authority (MBTA). Transit information.

44 WMATA - Washington Metropolitan Area Transit Authority (WMATA). Transit information.

45 SEPTA - Southeastern Pennsylvania Transportation Authority (SEPTA). Transit information.

46 CTA - Chicago Transit Authority (CTA). Travel info.

47 Seattle Transit - City of Seattle. Transit.

48 Maryland MTA - Maryland Department of Transportation Transit Administration (Maryland MTA). Transit information.

49 LA Metro - Los Angeles Metro (LA Metro). Transit information.

50 TriMet - TriMet. TriMet provides bus, light rail, and commuter rail transit services in the Portland, Oregon metro area.

51 PBOT-Equity - Portland Bureau of Transportation (PBOT). Equity Plans.

52 Seattle-Transit Equity - Seattle Department of Transportation. Transportation Equity Program.

53 Yeganeh 2018 - Yeganeh AJ, Hall RP, Pearce AR, Hankey S. A social equity analysis of the U.S. public transportation system based on job accessibility. Journal of Transport and Land Use. 2018;11(1):1039-1056.

54 Garrett 1999 - Garrett M, Taylor B. Reconsidering social equity in public transit. Berkeley Planning Journal. 1999;13:6-27.

55 Klingbaum 2021 - Klingbaum A, Afful A, Gunaseelan V, Sathiyamoorthy T. Impacts of light rail transit development on neighborhood health: A scoping review through a social determinants of health lens. Journal of Transport and Health. 2021;21:101063.

56 Hess 2020a - Hess CL. Light-rail investment in Seattle: Gentrification pressures and trends in neighborhood ethnoracial composition. Urban Affairs Review. 2020;56(1):154-187.

57 Heilmann 2018 - Heilmann K. Transit access and neighborhood segregation. Evidence from the Dallas light rail system. Regional Science and Urban Economics. 2018;73:237-250.

58 Appleyard 2019 - Appleyard BS, Frost AR, Allen C. Are all transit stations equal and equitable? Calculating sustainability, livability, health, & equity performance of smart growth & transit-oriented-development (TOD). Journal of Transport & Health. 2019;14:100584.

59 Tehrani 2019 - Tehrani SO, Wu SJ, Roberts JD. The color of health: Residential segregation, light rail transit developments, and gentrification in the United States. International Journal of Environmental Research and Public Health. 2019;16(19):3683.

60 NASEM-Thomas 2022 - Thomas DN, Heer N, Wyatt Mitchell I, et al. Racial equity, Black America, and public transportation, volume 1: A review of economic, health, and social impacts. Washington, D.C.: National Academies Press; 2022.

61 McAndrews 2022 - McAndrews C, Schneider RJ, Yang Y, et al. Toward a gender-inclusive Complete Streets movement. Journal of Planning Literature. 2022;38(1):3-18.