Carpool & rideshare programs

Evidence Rating  
Evidence rating: Expert Opinion

Strategies with this rating are recommended by credible, impartial experts but have limited research documenting effects; further research, often with stronger designs, is needed to confirm effects.

Disparity Rating  
Disparity rating: Potential to decrease disparities

Strategies with this rating have the potential to decrease or eliminate disparities between subgroups. Rating is suggested by evidence, expert opinion or strategy design.

Health Factors  
Date last updated

Carpool and rideshare programs help participants share transportation. Carpools and rideshares can be informal arrangements between individuals or be formally arranged through reservation-based ridesharing programs or on demand, dial-a-ride services1. Employers, along with state and local governments, often support the creation of carpools or vanpools, coordinate ridership, meeting points and drop-off locations, and may provide incentives such as preferential parking for participants2. In addition to bringing commuters to work or school, rideshares can bring participants to other locations such as health care clinics or grocery stores3, 4.

The evidence presented in this strategy does not include the services available through Uber, Lyft, or other for-profit, ride-hailing transportation network companies.

What could this strategy improve?

Expected Benefits

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

  • Reduced traffic congestion

  • Reduced emissions

  • Reduced vehicle miles traveled

Potential Benefits

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

  • Increased mobility

  • Improved quality of life

  • Reduced stress

What does the research say about effectiveness?

Carpool and rideshare programs are suggested strategies to reduce traffic congestion, decrease emissions per traveler, and reduce vehicle miles traveled (VMT)2, 5, 6, 7, 8. However, additional evidence is needed to confirm effects9.

Available research suggests that improving awareness, trust and willingness to ride with strangers10, 11, 12, and flexibility in scheduling may increase carpool use10, 11, 12, 13. Rideshare programs may also improve mobility and quality of life for older adults14, 15 and reduce stress for commuters16, 17. A California-based study found that vanpool commuters experienced lower rates of commuting stress than single-occupancy vehicle commuters16.

Transit incentives may increase the use of alternative transportation, which can include carpools and rideshares9. Incentives for carpooling and rideshares have the potential to reduce traffic congestion, reduce fuel consumption, reduce emissions per traveler, and improve air quality5, 8. A Seattle-based study suggests that an app-based carpooling system with incentives may increase commuter carpooling and reduce overall vehicle miles traveled (VMT) by decreasing the number of single-occupancy vehicle commuters in the region5. A study based in Arizona and Texas suggests that incentives may increase the use of carpooling for workplace commuting by males between the ages of 26-45; other factors which may contribute to carpool willingness include flexible departure time and the amount of time needed to find a parking spot18. Incentives that can increase carpool use include free or decreased toll rates2, 7, 19 and reduced parking prices for carpool or rideshare vehicles13, 20, 21. High gas prices13, 22 and high costs of parking for individual cars may also support carpooling13.

A California-based study suggests that children living further from school may be more likely to carpool, particularly children from families with two higher income earners or households headed by young, educated, females living in neighborhoods with many school-aged children3.

Experts recommend transit agencies establish public-private partnerships with other local stakeholders to identify the municipality’s needs, especially for mobility challenged populations, and tailor services appropriately18. Furthermore, experts suggest partners consider carpooling systems as a way to solve the first/last mile challenges that come with using public transit for commuting, particularly for mobility-challenged populations5. Studies suggest that carpool and rideshare programs can be cost-effective6, 7, 23, especially for longer commutes24. Expert analysis suggests that, as a climate change solution, carpool and rideshare initiatives have very low implementation costs and the potential for significant long-term cost savings and emissions reductions (9 to 11 gigatons of carbon dioxide over 30 years). However, carpool and rideshares’ effectiveness as a climate solution would be reduced if more sustainable solutions, such as walking, bicycling, or public transportation, are widely adopted instead8.

High occupancy vehicle lanes (HOVs) may increase carpooling and ridesharing in some circumstances25, 26, 27, 28; however, local context strongly influences the success or failure of HOVs and carpool or rideshare programs25, 28.

How could this strategy advance health equity? This strategy is rated potential to decrease disparities: suggested by expert opinion.

Carpool and rideshare programs have the potential to decrease disparities in access to transportation for mobility-challenged populations, such as older adults, individuals with low incomes receiving Medicaid, and refugee and asylum seeking women14, 42, 43, 44.

Rideshare programs can support the mobility needs of older adults, particularly those who stop driving for health reasons; however, older adults with lower incomes may limit use based on cost if rideshares are through for-profit companies14.

Rideshare programs may be offered by health care organizations, along with other forms of nonemergency medical transportation, to bring mobility-challenged patients to appointments. Patients participating in a rideshare program to bring them to MRI appointments were more likely to be older, unemployed, and without commercial insurance, and to arrive on time as a result of the program42. However, depending on the type of vehicle and the driver’s training, rideshares may not meet the needs of passengers with mobility disabilities that require accessible vehicles and drivers trained to physically assist them when entering and exiting the vehicle45.

A rideshare program for pregnant women receiving Medicaid that provides rides to doctors’ appointments along with a limited number of trips to grocery stores, pharmacies, or food banks can increase participants’ satisfaction with transportation services, when compared to traditional nonemergency medical transportation services43. A rideshare program offered by an urban health clinic to refugee and asylum seeking women who report experiencing transportation insecurity may increase access to care by reducing no-show rates, which can make the program cost-efficient for the clinic44.

What is the relevant historical background?

Transportation in the U.S. has been shaped by many factors, including car ownership, residential living patterns, federal funding, and the mass construction of interstate highways46. In the 19th century and early 20th century, streetcars helped define residential and commercial areas in cities47, while roads extended from railroad stops to connect rural areas to rail lines, bringing produce to urban areas and manufactured goods back to farming communities48.

Following World War II, carpooling emerged as a commuting method, with riders and drivers manually matching on bulletin boards posted in workplaces or through connections with co-workers, family, or friends with similar home-to-work or home-to-school trips49. By the 1970s, large employers recognized carpooling as a way to bring employees living at a distance to site and began identifying possible carpool matches for staff based on employee travel data and established vanpools, which could transport groups of 7-15 employees from a set meeting point, often in a rural area16, 49.

To increase access to transportation for the mobility-challenged, non-profit organizations established rideshare programs, beginning in 1964 with the Friends In Service Helping (FISH) program in West Springfield, Massachusetts14. At the federal level, the Rehabilitation Act of 1973 was first passed to improve transportation access for individuals with disabilities and older adults. In 1990, the Americans with Disabilities Act (ADA) made additional attempts to improve transportation access and prohibited discrimination against people with disabilities, which included transportation accommodations50. Yet even with these laws, it is still challenging to access reliable, accessible transportation. Older adults, individuals with disabilities, and other non-drivers require mobility options to protect their health as well as their social and civic engagement51.

Technology advances in the late 20th century expanded access to both carpool and rideshare programs. Carpooling remained a popular commuting method through the mid-1980s5, and in the 1990s, carpoolers could be matched via telephone and later through email or websites49, even as commuting in single-occupancy vehicles became more common5. As the internet, smartphones, and mobile apps became the primary form of matching for modern carpool and rideshare programs, along with non-commuter ride-hailing or ride-sourcing trips5, 14, 49, access for those with smartphones, broadband services, and technology literacy has increased, while access for those without these devices and/or skills has become increasingly difficult5.

Equity Considerations
  • How can local businesses support carpool matches between employees commuting to work from outlying areas? What funding is needed to establish employer-sponsored vanpools (i.e., purchase vans, insurance, etc.)?
  • What partnerships between employers and local or state government departments can help fund and/or coordinate vanpools? What contingency plans can be implemented with employer-sponsored vanpool programs to provide a guaranteed ride home in case of van mechanical issues or unexpected rider schedule changes?
  • How are local ridesharing and carpooling programs equipped to provide services in multiple languages? Are program materials readily available in multiple languages and large print? Are materials also available over the phone, electronically, and in-person so potential participants have multiple ways to access the information?
  • Which organizations in your community are already offering transportation services to particularly vulnerable residents such as older adults or individuals with disabilities? Who can coordinate partnerships between these organizations and transit agencies to learn more about community needs, create plans to fill transit gaps, and coordinate ride-sharing services?
Implementation Examples

Department of Transportation (DOT) offices in many states provide information on carpool and rideshare programs; some programs feature searchable databases, such as Oregon DOT’s Get There Connect and the Washington State DOT’s RideshareOnline program, which also includes SchoolPool carpooling programs29, 30, 31. State government agencies can also directly support vanpools, generally in state-owned vehicles. California Vanpool Authority’s CalVans program, for example, brings workers to rural farms32, 33, the Wisconsin Department of Administration’s (WI DOA’s) state vanpool brings state and non-state employees from distance areas to jobs in Madison, WI34, and the Michigan DOT’s MichiVan commuter vanpool program supports employers interested in developing vanpool and rideshare programs for employees35.

City or county governments may also support ridesharing efforts. King County, Seattle offers vanpool and vanshare programs which can respectively set their own routes/schedules or transport commuters between local transit hubs and workplaces36. King County Metro also partners with the City of Redmond and Greater Redmond TMA on Go Redmond, a program offering personalized commuting support for the community, including guidance on finding carpool partners and vanpools through their website, available in several languages37. In Michigan, the Ann Arbor Area Transportation Authority’s TheRide features incentive programs for commuters to carpool, vanpool, use park-and-rides, and access emergency rides home38.

Carpool and rideshare programs are also available by region. Commuter Connections provides free services to the Metropolitan Washington, D.C. area, including carpool and vanpool matching, park-and-ride lots and high occupancy vehicle (HOV) lane information, transit routes/schedules, bike to work information, a regional guaranteed ride home program, and more39. In Central Oregon, Commute Options’ vanpool programs are noted for providing additional community benefits, including reduced traffic congestion, parking needs, and greenhouse gas emissions40.

Rideshare programs for health-related needs are available to qualifying passengers, often through government agencies. In California, Medi-Cal transports eligible mobility-challenged or pregnant patients to medical, mental health, dental, or substance abuse disorder appointments, as well as to pick up medical supplies and prescriptions4. Massachusetts Human Service Transportation Office offers resources for patients, families, and medical providers to arrange transportation to both local and long distance medical appointments, including programs specific to older adults, people with disabilities, and veterans41.

Implementation Resources

Resources with a focus on equity.

NCTR-Ridematching - National Center for Transit Research (NCTR). Ridematching software: List of programs with ridematching systems. Center for Urban Transportation Research (CUTR), University of South Florida (USF).

RideshareOnline - Brilliant commuters know smart ways to get around. Washington State Department of Transportation.

MA HSTO-MassMobility - Massachusetts Human Service Transportation Office (MA HSTO). MassMobility. Health care transportation.

Project Drawdown-Carpooling - Project Drawdown. Climate solutions: Carpooling.


* Journal subscription may be required for access.

1 Ouyang 2021 - Ouyang Y, Yang H, Daganzo CF. Performance of reservation-based carpooling services under detour and waiting time restrictions. Transportation Research Part B: Methodological. 2021;150:370-385.

2 UC Davis-Yura 2006 - Yura EA, Eisinger D, Deb Niemeier. A review of on-road vehicle mitigation measures. Davis: University of California, Davis; 2006.

3 Rafiq 2020 - Rafiq R, Mitra SK. Shared school transportation: Determinants of carpooling as children’s school travel mode in California. Transportation. 2020;47:1339-1357.

4 CA DHCS-Transportation - California Department of Health Care Services (CA DHCS). Transportation services.

5 Shen 2021 - Shen Q, Wang Y, Gifford C. Exploring partnership between transit agency and shared mobility company: An incentive program for app-based carpooling. Transportation. 2021;48:2585-2603.

6 ICF Consulting 2006 - ICF Consulting. Bay Area Air Quality Management District performance review of selected TFCA project types: Final report. Fairfax: ICF Consulting; 2006.

7 RAND-Sorenson 2008 - Sorenson P, Wachs M, Min EY, et al. Moving Los Angeles: Short-term policy options for improving transportation. Santa Monica: RAND Corporation; 2008: Monograph Report 748.

8 Project Drawdown-Carpooling - Project Drawdown. Climate solutions: Carpooling.

9 Graham-Rowe 2011 - Graham-Rowe E, Skippon S, Gardner B, Abraham C. Can we reduce car use and, if so, how? A review of available evidence. Transportation Research Part A: Policy and Practice. 2011;45(5):401-418.

10 Chaube 2010 - Chaube V, Kavanaugh AL, Pérez-Quiñones MA. Leveraging social networks to embed trust in rideshare programs. In: Proceedings of the 43rd Hawaii International Conference on System Sciences - 2010. Washington, D.C.: Institute of Electrical and Electronics Engineers (IEEE); 2010.

11 Deakin 2010 - Deakin E, Frick KT, Shively KM. Markets for dynamic ridesharing? Case of Berkeley, California. Transportation Research Record: Journal of the Transportation Research Board. 2010;2187:131-137.

12 Levofsky 2001 - Levofsky A, Greenberg A. Organized dynamic ride sharing: The potential environmental benefits and the opportunity for advancing the concept. Washington, D.C.: Transportation Research Board 2001 Annual Meeting. 2001: Working Paper 01-0577.

13 Erdogan 2015 - Erdogan S, Cirillo C, Tremblay JM. Ridesharing as a green commute alternative: A campus case study. International Journal of Sustainable Transportation. 2015;9(5):377-388.

14 Freund 2020 - Freund K, Bayne A, Beck L, et al. Characteristics of ride share services for older adults in the United States. Journal of Safety Research. 2020;72:9-19.

15 Silvis 2009 - Silvis J, Niemeier D. Social network and dwelling characteristics that influence ridesharing behavior of seniors. Transportation Research Record: Journal of the Transportation Research Board. 2009;(2118):47-54.

16 Ditmore 2018 - Ditmore CJ, Deming DM. Vanpooling and its effect on commuter stress. Research in Transportation Business and Management. 2018;27:98-106.

17 Robbins 2015 - Robbins WA, Berman BA, Stone DS. Health effects of vanpooling to work. Workplace Health & Safety. 2015;63(12):554-563.

18 Chen 2021 - Chen TY, Jou RC, Chiu YC. Using the multilevel random effect model to analyze the behavior of carpool users in different cities. Sustainability. 2021;13(2):937.

19 Li 2007 - Li J, Embry P, Mattingly SP, et al. Who chooses to carpool and why? Examination of Texas carpoolers. Transportation Research Record: Journal of the Transportation Research Board. 2007;2021:110-117.

20 Salon 2012 - Salon D, Boarnet MG, Handy S, Spears S, Tal G. How do local actions affect VMT? A critical review of the empirical evidence. Transportation Research Part D: Transport and Environment. 2012;17(7):495-508.

21 Willson 2008 - Willson RW, Brown KD. Carbon neutrality at the local level: Achievable goal or fantasy? Journal of the American Planning Association. 2008;74(4):497-504.

22 Javid 2016 - Javid RJ, Nejat A, Salari M. The environmental impacts of carpooling in the United States. 2016.

23 Gallivan 2011 - Gallivan F, Ang-Olson J, Liban CB, Kusumoto A. Cost-effective approaches to reduce greenhouse gas emissions through public transportation in Los Angeles, California. Transportation Research Record: Journal of the Transportation Research Board. 2011;2(2217):19-29.

24 Silva-Send 2013 - Silva-Send N, Anders S, Narwold A. Cost effectiveness comparison of certain transportation measures to mitigate greenhouse gas emissions in San Diego County, California. Energy Policy. 2013;62:1428-1433.

25 Cui 2022 - Cui D, Wang Z, Liu P, et al. Battery electric vehicle usage pattern analysis driven by massive real-world data. Energy. 2022;250:123837.

26 Zhong 2020a - Zhong L, Zhang K, Nie Y, Xu J. Dynamic carpool in morning commute: Role of high-occupancy-vehicle (HOV) and high-occupancy-toll (HOT) lanes. Transportation Research Part B: Methodological. 2020;135:98-119.

27 Hughes 2019 - Hughes JE, Kaffine D. When should drivers be encouraged to carpool in HOV lanes? Economic Inquiry. 2019;57(1):667-684.

28 Shewmake 2012 - Shewmake S. Can carpooling clear the road and clean the air?: Evidence from the literature on the impact of HOV lanes on VMT and air pollution. Journal of Planning Literature. 2012;27(4):363-374.

29 Get There Oregon - Get There Oregon. Learn. Thrive. Connect. Get There and its partners help commuters and employers shift commute habits and work practices one trip at a time.

30 WSDOT-Carpool - Washington State Department of Transportation (WSDOT). Carpools & vanpools.

31 RideshareOnline - Brilliant commuters know smart ways to get around. Washington State Department of Transportation.

32 Sampson 2014 - Sampson R. CalVans: An easy ride to the hard work on a farm. California Vanpool Authority. 2014.

33 CalVans - California Vanpool Authority (CalVans). California’s single source for ridesharing to work or college in a CalVans vehicle.

34 WI DOA-Vanpool - Wisconsin Department of Administration (WI DOA). Joining a vanpool.

35 MDOT-Rideshare - Michigan Department of Transportation (MDOT). Michigan Rideshare: Share the ride, share the cost.

36 King County-Vanpool - King County, Seattle. Metro travel options: Vanpool and vanshare.

37 Go Redmond - Go Redmond. Finding ridematches: Step by step guide for finding carpool partners and vanpools on Go Redmond. King County Metro, City of Redmond, and Greater Redmond TMA; King County, Washington.

38 TheRide - TheRide. Commuter services. Ann Arbor Area Transportation Authority, Michigan.

39 Commuter Connections - Commuter Connections. Commuting solutions for Washington area employers: Resources.

40 Commute Options-Vanpool - Commute Options. Vanpool. Bend, OR.

41 MA HSTO-MassMobility - Massachusetts Human Service Transportation Office (MA HSTO). MassMobility. Health care transportation.

42 Whorms 2021 - Whorms DS, Narayan AK, Pourvaziri A, et al. Analysis of the effects of a patient-centered rideshare program on missed appointments and timeliness for MRI appointments at an academic medical center. Journal of the American College of Radiology. 2021;18(2):240-247.

43 Lynch 2023 - Lynch CD, Conroy S, Jackson KA, Smith RM, Hade EM. Access to rideshare and satisfaction, prenatal healthcare utilisation, and preterm delivery among pregnant Medicaid recipients: A randomised controlled trial. Paediatric and Perinatal Epidemiology. 2023;37(3):201-211.

44 Vais 2020 - Vais S, Siu J, Maru S, et al. Rides for refugees: A transportation assistance pilot for women’s health. Journal of Immigrant and Minority Health. 2020;22:74-81.

45 Eisenberg 2020 - Eisenberg Y, Owen R, Crabb C, Morales M. Rideshare transportation to health care: Evidence from a Medicaid implementation. American Journal of Managed Care. 2020;26(9):1-20.

46 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.

47 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.

48 Schauer 2003 - Schauer P. The trip to town: Rural transportation patterns and developments since 1900. Transportation Research Board (TRB): TR News. 2003;225:4-11.

49 Sun 2022 - Sun Y, Chen S, Guo Q. Evaluating the environmental benefits of personalized travel incentives in dynamic carpooling. KSCE Journal of Civil Engineering. 2022;26(7):3082-3093.

50 US DOT-FTA-NTD History - U.S. Department of Transportation (U.S. DOT), Federal Transit Administration (FTA). History of the National Transit Database (NTD) and transit in the United States. 2017.

51 SGA-Thakkar 2023 - Thakkar A, Smith JR, Bellis R, et al. An active roadmap: Best practices in rural mobility. Smart Growth America (SGA) and National Complete Streets Coalition. 2023.