Public Transportation System: Introduction or Expansion
What is the public transportation system?
- Public Health Innovators’ Stories: Public Transportation System: Introduction or Expansion
- CDC and U.S. Department of Transportation:Transportation and Health Toolexternal icon
- CDC’s Transportation Health Impact Assessment Toolkit
- American Public Health Association Transportation and Healthexternal icon
- U.S. Department of Transportation: Public Transitexternal icon
- CDC: Motor Vehicle Prioritizing Interventions and Motor Vehicle Prioritizing Interventions and Cost Calculator for States (MV PICCS)
- Manual on Pedestrian and Bicycle Connectionspdf iconexternal icon to Transit
- National Association of City Transportation Officials Transit Street Design Guideexternal icon
Public transportation systems include a variety of transit options such as buses, light rail, and subways. These systems are available to the general public, may require a fare, and run at scheduled times. The purpose of introducing or expanding public transportation is to increase access to and use of public transit while, at the same time, reducing motor vehicle miles driven and traffic congestion.
Public transportation systems are often implemented at the local or regional level and can be supported by federal initiatives, such as the Fixing America’s Surface Transportation (FAST) Act. [1, 2] Los Angeles County is one example of a region that expanded its public transportation system using local, state, and federal funding.[3, 4]
What is the public health issue?
Transportation systems help ensure that people can reach everyday destinations, such as jobs, schools, healthy food outlets and healthcare facilities, safely and reliably. Public transportation services play an important role for people who are unable to drive, including those without access to personal vehicles, children, individuals with disabilities, and older adults.[5,6] The U.S. transportation infrastructure focuses on motor vehicle travel (e.g., passenger cars, vans, SUVs, pickup trucks, and other light trucks) and provides limited support for other transportation options.[ 7] According to the U.S. Census Bureau, in 2013 approximately 86 percent of all workers traveled to work by private vehicle, and 76 percent drove alone. Also in 2013, 69 percent of urban households and 14 percent of rural households had access to public transit. Although using public transportation has historically been safer than travel in passenger vehicles, passenger vehicle travel has grown more quickly than other modes of travel.[1,7,9] Motor vehicle crashes continue to be the leading cause of injury-related death for many age groups.[7,10] In 2013, motor vehicle crashes were the second leading cause of death among individuals aged 13 to 25 years.
Public transportation systems provide opportunities for increased physical activity in the form of walking or biking on either end of the trip (e.g., from home to bus stop or from train stop to office) and reduced motor vehicle travel.[12-15] Despite these benefits, many Americans view walking and bicycling within their communities unfavorably because of barriers such as disability, age, chronic disease, inconvenience or safety concerns about traffic and a lack of sidewalks, crosswalks, and bicycle facilities.[7,16] Many people aren’t meeting the recommendations for physical activity; the lack of physical activity contributes to obesity, diabetes, heart disease, stroke, and other chronic health conditions in the U.S. [7,16]
Air pollution from motor vehicles continues to contribute to adverse respiratory and cardiovascular health effects.[7,18] Nitrogen oxides and volatile organic compounds react with sunlight to create ozone. Carbon monoxide, nitrogen oxides, and ozone are associated with a variety of health problems including myocardial ischemia, chest pain, coughing, throat irritation, and airway inflammation, and can worsen bronchitis, emphysema, and asthma.[20-22] Particulate matter, which is produced by engine exhaust and tire and brake wear, is associated with an increased risk of respiratory and cardiovascular disease.[23-25]
What is the evidence of health impact and cost effectiveness?
Public transportation systems are associated with reductions in several health risk factors such as motor vehicle crashes, air pollution, and physical inactivity. The U.S. Department of Transportation reported that public transportation (school, intercity, transit bus, light rail transit, and subway) accounted for less than one percent of transportation fatalities in 2011, while private passenger vehicles accounted for more than 75 percent of transportation fatalities.[1, 25] An analysis of the transportation fatality risk in the U.S. found that the fatality rates per billion passenger miles traveled between 2000 and 2009 were 0.11 for buses, 0.24 for urban mass transit rail trains, 0.43 for passengers on commuter rails, and 7.28 for drivers or passengers in a car or light truck. For every passenger mile traveled, public transportation produces only a fraction of the harmful pollution of private vehicles: only five percent as much carbon monoxide, less than eight percent as many volatile organic compounds, and nearly half as much carbon dioxide and nitrogen oxides.
A systematic review examining public transportation use and physical activity found that use of public transport was associated with an additional 8 to 33 minutes of walking per day. A study of the impact of adding light rail stations in Los Angeles found it to be associated with an increase in daily physical activity among residents with previously lower physical activity levels. The expansion was also associated with a reduction in vehicle miles traveled and their related emissions. Another study found that train commuters took an average of 30 percent more steps per day than car commuters. A study of 130 U.S. cities found that each rail passenger mile represents a reduction of three to six automobile passenger miles—through direct substitution and indirectly through the creation of compact, mixed-use transit-oriented developments that foster walking and cycling and reduced automobile ownership. A final study, looking at zoning for TODs, found that this type of zoning was associated with significantly higher rates of public transportation to work and active transportation to work. 
A descriptive cost analysis examined the value of the health benefits, which included fewer traffic crashes, less air pollution and increased physical fitness, of increasing the proportion of the population that has access to public transit. The analysis estimated that if a city with a typical quality North American public transit service improved to high quality (i.e., fast, convenient and comfortable) urban rail or bus rapid transit service, the per capita annual health benefits would be $355. If improvements were made to achieve a high quality transit service with walkable, mixed-use development around stations, the per capita annual health benefits would be $541. It also estimated that for a city with a million residents, an increase in the proportion of households located in transit-oriented developments from 10 percent to 20 percent would produce nearly $71 million of total annual health benefits, and an increase from 10 percent to 40 percent would generate more than $216 million of total annual health benefits.
A cost-benefit analysis that examined the impact of expanding public transportation capacity by converting a lane for bus rapid transit found an association with positive net benefits to society, including travel time savings, travel cost savings, and emissions reduction. 
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- Robert Wood Johnson Foundation, The University of Wisconsin Population Health Institute. Public Transportation: System introduction or expansion. County Health Rankings & Roadmaps. Public transportation systemsexternal icon. Published June 29, 2017. Accessed August 20, 2018.
- The Federal Transportation Act: The Fixing America’s Surface Transportation (FAST) Act; 2015.
- The Los Angeles County Metropolitan Transportation Authority (Metro). Project, Programs and Plans. Transportation Fundingexternal icon. Published 2016. Accessed August 20, 2018.
- America’s Infrastructure Scores a D+. America Society of Civil Engineers’ 2017 Infrastructure Report Cardexternal icon. Published 2017. Accessed April 19, 2018.
- Connectivity: Relationship to Public Healthexternal icon. Published October 26, 2015. Accessed August 20, 2018.
- Lindsay S, Lamptey DL. Pedestrian navigation and public training interventions for youth with disabilities: A systematic reviewexternal icon. Disability and Rehabilitation. 2018:1-15. Accessed 2018.
- CDC Transportation Recommendations. Centers for Disease Control and Prevention. Transportation Recommendations. Published February 7, 2018. Accessed August 23, 2018.
- McKenzie B. Who Drives to Work? Commuting by Automobile in the United States: 2013pdf iconexternal icon. United States Census Bureau. American Community Survey Reports. August 2015. Accessed 2018.
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- Injury Prevention & Control. Centers for Disease Control and Prevention. Ten Leading Causes of Death and Injury. Published April 13, 2018. Accessed August 20, 2018.
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- Besser LM, Dannenberg AL. Walking to Public Transit: Steps to Help Meet Physical Activity Recommendationspdf icon. American Journal of Preventative Medicine. 2005;29(4):273-280. Accessed 2018.
- Miller HJ, Tribby CP, Brown BB, et al. Public transit generates new physical activity: Evidence from individual GPS and accelerometer data before and after light rail construction in a neighborhood of Salt Lake City, Utah, USAexternal icon. Health & Place. 2015;36:8-17. Accessed 2018.
- 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 Constructionexternal icon. American Journal of Public Health. 2015:105(7):1468-1474. Accessed 2018.
- Park K, Ewing R, Scheer BC, Tian G. The impacts of built environment characteristics of rail station areas on household travel behavior. Cities. 2018;74:277-283.
- U.S. Department of Health and Human Services. Step It Up! The Surgeon General’s Call to Action to Promote Walking and Walkable Communitiesexternal icon. Published 2015. Accessed 2018
- U.S. Department of Health and Human Services. Healthy People 2020. Physical Activityexternal icon. Accessed August 20, 2018.
- Caiazzo F, Ashok A, Waitz IA, Yim SH, Barrett SR. Air pollution and early deaths in the united states. Part i: Quantifying the impact of major sectors in 2005external icon. Atmospheric Environment. 2013;79:198-208. Accessed 2018.
- U.S. Environmental Protection Agency. Ozone Pollutionexternal icon. Published 2018. Accessed August 20, 2018.
- U.S. Environmental Protection Agency. Basic Information about Ozoneexternal icon. Published June 22, 2018. Accessed August 20, 2018.
- U.S. Environmental Protection Agency. Carbon Monoxide (CO) Pollution in Outdoor Airexternal icon. Published January 16, 2018. Accessed August 20, 2018.
- U.S. Environmental Protection Agency. Nitrogen Dioxide (NO2) Pollutionexternal icon. Published April 20, 2018. Accessed August 20, 2018.
- Hung-Lung C, Yao-Sheng H. Particulate matter emissions from on-road vehicles in a freeway tunnel studyexternal icon. Atmospheric Environment. 2009;43(26):4014-4022. Published August 2009. Accessed 2018.
- Anderson JO, Thundiyil JG, Stolbach A. Clearing the air: A review of the effects of particulate matter air pollution on human healthexternal icon. Journal of Medical Toxicology. 2012;8(2):166-175. Published December 23, 2011. Accessed 2018.
- U.S. Department of Transportation Bureau of Transportation Statistics. National Transportation Statisticsexternal icon 2016. Published 2016. Accessed August 20, 2018.
- Savage I. Comparing the fatality risks in United States transportation across modes and over time. Research in Transportation Economics. 2013;43(1):9-22.
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- Litman T. Evaluating Public Transportation Health Benefitspdf iconexternal icon. Victoria Transport Policy Institute. Published June 14, 2010. Accessed August 20, 2018.
- Ang-Olson J, Mahendra A. Cost/Benefit Analysis of Converting a Lane for Bus Rapid Transit—Phase II Evaluation and Methodology. Transportation Research Board. 2011.