Carpools, Vanpools & Ridesharing

The EPA's Carpool Incentive Programs as part of its Commuter Choice Leadership Initiative (CCLI) defines carpools as consisting of "two or more persons driving together in a privately owned vehicle." It identifies that while some employees choose to carpool regardless of incentives, carpool incentive programs can help to encourage increased participation in carpooling. Possible incentive programs include reduced cost or free parking, preferred or reserved parking, and/or reward programs. These incentives, along with rideshare matching assistance, can be enacted solely by employers, but cities can get involved too by making vehicles (especially low emission vehicles) available to participating employers as is the case in the city of Irvine, CA through its Zero Emission Vehicle-Network Enabled Transport program (ZEV-NET).

Strategies and Greenhouse Gas Reduction

  • Encourage carpooling, vanpooling, and mass transit use
  • Encourage carpooling, vanpooling, and mass transit use for municipal employees
  • Create 5 new City vanpools by 2012
  • 1 percent of municipal employees switch from single-occupancy vehicles (SOVs) to bus.
  • Promote the online service among municipal employees, so that more potential carpool and vanpool riders can be identified in the City.
  • Promote the online service so that more potential carpool and vanpool riders can be identified in the City.
  • It is estimated that Pierce Transits plans to purchase 80 new vans for vanpool use by 2012 could result in a CO2 emissions reduction of 1385-2541 metric tons by 2012 depending on the type of fuel used. This estimate is based on one vanpool replacing eight single occupancy vehicles that average 7176 miles commuting per vehicle per year.
  • It is estimated that if 5 new City vanpools are created by 2012, each vanpool will reduce CO2 emissions by 40 tons, resulting in a 200 ton decrease in CO2 emissions by 2012.
  • By promoting online rideshare services it is estimated that 350 new two-person carpools could be created by 2012 which could result in a 700 ton decrease in CO2 emissions by 2012.

Additional Strategies

  • Provide guaranteed ride home (GRH) programs to commuters who carpool, use transit, bike or walk so they can get home quickly in the event of an emergency
  • Park-and-ride lots to serve as meeting place for potential carpool participants who do not live in immediate proximity of other employees

Cost to the City

Costs to the city may include the purchase of vehicles for carpooling and vanpooling, allocating parking spaces for use by carpoolers, and costs associated with publicizing regional rideshare organizations and alternative transportation options. The Portland Department of Transportation spent $150,000 for its social marketing campaign, Travel Smart.


  • Tacoma employers: Those who will be partnering with the city to provide incentives to employees
  • Tacoma employees: Those who will be carpooling
  • The City of Tacoma: Creating partnerships with city employers and providing funding and/or vehicles
  • Regional rideshare organizations (
  • Pierce Transit

Barriers for employers

  • Developing a successful and accessible rideshare matching program; also involves regional rideshare organizations
  • Designating preferred parking spaces for carpoolers. To be most effective, spaces should be located in desirable locations: near building entrances, covered, and/or attended.
  • Costs associated with providing carpoolers with discounted or free parking
  • Matching employee schedules-guaranteeing that carpooling employees are able to arrive and depart at the same times
  • Enforcement of carpooling-ensuring that registered carpoolers are actually carpooling, carpool parking passes are not being abused, etc.
  • Proportion of budget put towards offering monetary rewards or prizes to participating carpoolers

Barriers for City

  • Deciding what employers/employees have access to city-funded vehicles

Benefits cited by the EPA's Carpool Incentive Programs:

Employee benefits

  • Decreased individual transportation costs through cost-sharing
  • Less wear and tear on vehicles
  • Time savings in regions with high-occupancy vehicle (HOV) lanes
  • Freedom to talk, eat, sleep, or read while commuting
  • Less commute-related stress
  • Increased job satisfaction

Employer benefits

  • Fewer parking spaces needed to accommodate employees
  • Increased productivity and morale
  • Improve employee recruiting and retention
  • Decreased scheduling interference due to traffic-induced unpredictability

City benefits

  • Decreased traffic congestion on city streets
  • Increased availability of parking spaces
  • Increased air quality


  • City of Tacoma
  • Tacoma employers
  • Tacoma employees
  • Regional rideshare organizations (
  • Pierce Transit

As cited by the EPA's Carpool Incentive Programs:

  • Identify employers in urban settings with limited parking and large numbers of employees. The higher density the employment setting, the more likely a carpool program is to succeed. Also, when more employees are present at a single site, convenient rideshare matches are more likely to be found.
  • Determine potential for carpooling by investigating employee's residential locations (zip code), commute patterns, regularity of work schedules, and level of interest in carpooling and/or what incentives would encourage them to carpool. The Association for Commuter Transportation (ACT) recommends their Commute Mode Survey which can be obtained through their Transportation Demand Tool Kit.
  • Consider and design an enforcement strategy for regulating carpool programs. Gated or attended parking is a possible solution.
  • Use survey results to decide on incentives that are appropriate to particular circumstances.
  • Connect employers with rideshare matching organizations
  • Centralize commute options information such that it is easy for employees to access and use
  • Develop guidelines, registration procedures, and eligibility requirements for carpooling program
  • Announce and implement the carpooling program by advertising, putting on special promotional days, hosting a "kick off" event in which city-funded vehicles are unveiled and/or representatives from rideshare organizations are present, etc.
  • Continue to monitor, maintain and market the program once implemented in order to make necessary adjustments.

Success Stories
The first example is an employer success story, but it relies on a publicly funded rideshare organization. The program could also benefit from city involvement and/or be applied to carpooling programs for employees in public buildings.

Emory University-Atlanta, Georgia
Emory University has about 14,000 faculty and staff and contains a major hospital and clinic. Administered by the university's Alternative Transportation office, the univeristy's carpool program in 2001 consisted of 400 carpoolers registered in 170 carpools (an average vehicle occupancy of 2.08 persons). The program was developed in order to alleviate parking congestion on campus, and it therefore provides incentives to carpoolers by way of reduced parking rates and/or reserved spaces. The program distinguishes three categories of carpoolers based on the number of full-time registered employees in the carpool. The program is publicized through events such as commuter fairs and Staff Days, as well as e-mail lists. Interested carpoolers register with Atlanta's Commute Connections rideshare service. The program is enforced by issuing special hangtags for carpool vehicles, gated parking lots, and requiring carpoolers to re-register annually.
Contact: Wanda Teichert, Program Development Coordinator with the Alternative Transportation office

City Success Stories

Irvine, California-ZEV-NET Shared-Use Vehicles
The Zero Emission Vehicle-Network Enabled Transport program (ZEV-NET) is public-private partnership that was implemented in April of 2002, which provides the employees of participating employers with electric (zero-emission) vehicles for transportation to and from the Irvine Transportation Center. Eligible drivers use a Web-based system to reserve vehicles for use during the day and vehicles are returned to the Transportation Center at the end of the day to be recharged. The city has experienced benefits ranging from reduced traffic congestion in the city, cleaner air quality, and raised awareness of alternate fuels, and the promotion of mass transit and carpool use.

Portland, Oregon-City Transit-Pass Subsidy Programs
The Portland Office of Transportation's Trip Reduction Incentive Program (TRIP) provides city employees with either a $25/month bus pass, carpool parking, or bike/walk incentive. The program was initiated in 1995, and through 2004 has resulted in a 20 percent decrease in weekly automobile trips to the downtown area. Approximately 1,300 of the 2,700 downtown employees have participated in the program.

Portland, Oregon-Travel Smart Program
The Portland Department of Transportation's (PDOT) Travel Smart program is an individualized marketing campaign that uses surveys to identify individuals that are interested in changing their travel habits and provides them with information about transportation alternatives such as transit, biking, walking or carpooling. The project was first introduced in Southwest Portland in 2002, costing $150,000, and through 2004 has contacted about 10,000 local residents per year and resulted in 440,000 fewer vehicle miles traveled per year.

Portland, Oregon-Online Ridesharing Service
The PDOT has promoted the city's online ridesharing service,, through advertising on city buses, by mail, and through transportation events. Since it's introduction in 2002 through 2004, more that 2,000 people have participated in the service and the PDOT is confident that the program is on schedule to achieving it's goal of reducing 70,000 metric tons of CO2 and 161 million vehicle miles traveled by 2012.