Passenger-Miles per Gallon
Passenger-miles per gallon (pmpg) is a metric for comparing passenger vehicle travel across modes. Transportation system efficiency increases as the number of passengers increases or as the vehicle fuel economy increases for each transportation mode.
|Car – national average||27.5||1.5||42.4|
|Car – high occupancy||27.5||5||137.5|
|Pickup Truck – national average||20.2||1.8||36.4|
|Pickup Truck – high occupancy||20.2||5||101|
|Transit Bus – national average**||3.4||7.7||26.4|
|Transit Bus – high ridership||3.4||40||137.2|
|Transit Train – national average**||6||23.5||141|
|Transit Train – high ridership||6||100||600|
* All fuel converted to gallons of gasoline on an energy content basis. For trains, most of this fuel is electricity.
** National average ridership numbers are from table 2.13 of the Transportation Energy Data Book.
Public transportation in the United States includes buses, bus rapid transit, trolleys, rail, and ferries. Transit buses are particularly well-suited for alternative fuels, and nearly 60% run on these lower-emissions, cost-saving options. Since transit buses can carry more passengers, they have the potential to achieve a higher passenger-mile per gallon.
Ridership determines the quality and impact of public transportation. Higher ridership can lead to increased service frequency and efficiency through reduction in vehicle miles traveled (VMT), congestion, and fuel used by private vehicles. The COVID-19 pandemic has had a dramatic impact on public transit ridership, revenue, and operations, but many frontline and essential workers are continuing to use public transit to travel to their jobs. The Bipartisan Infrastructure Law of 2021 allocates funds to support the recovery of public transit operations and address four priorities: safety, modernization, climate, and equity. Corporate decision makers and transportation planners can use the following strategies to help build strong ridership.
Making public transportation convenient can be a good way for transportation planners to boost ridership. Dedicated or “bus rapid transit” lanes and the use of high occupancy vehicle (HOV) lanes can reduce travel time for public transportation. Effective public transportation is also more convenient when people find it predictable. Public transportation providers can make their services more predictable by publishing schedules and communicating status updates. Updating service status often and providing those updates via easily accessible mobile applications such as Google Maps, also increases predictability. Some public transportation providers use geotracking systems such as NextBus to help riders track schedules and delays. Public transportation providers can also make their services more convenient by offering flexible payment options such as app-based services that integrate payment for a range of mobility options, such as micromobility and ride hailing, as part of a common payment platform.
Another way to facilitate public transportation ridership is to help people complete the first or last leg of their trip and get to the transit stop. Helping passengers link multiple transportation modes is key. Some public transportation agencies offer mobile ticketing apps or pre-loaded transit cards. In some cases, these are interoperable with bike sharing systems or other micromobility services. Making bicycle or scooter storage available on buses or at transit stations can also enable travelers to move between transportation modes easily. Public transportation agencies are also forming partnerships with transportation network companies and micromobility providers to improve mobility choices for customers.
The COVID-19 pandemic has dramatically affected the public perception of shared modes of transportation. Argonne National Laboratory, as part of the U.S. Department of Energy’s SMART Mobility Consortium, worked with the Chicago Transit Authority and the Chicago Department of Transportation to analyze how possible future scenarios may impact bus and train boardings, congestion, energy consumption, emissions, the economy, and equity. They also quantified the individual and simultaneous impacts of main levers like service cuts, telecommuting, risk perception, and load limits. Through a dozen scenarios, researchers identified that if the public’s risk perception remains and employees continue to telecommute at least one day per week, the decline in ridership would cause a 22% slowdown of vehicle speed and an 8.5-minute increase in travel time, along with the use of 500,000 additional gallons of fuels per day and a 15-minute increase in trip time for single passenger vehicles due to congestion. This would be due to a combination of fewer transit vehicles due to ridership decline and an increase in single-occupancy vehicles on the road because of risk perception and reduced transit schedules.
One study conducted between April and June of 2020 in Chicago showed that 77% of respondents considered public transit to have a “high” or “very high” risk of COVID-19 exposure, compared to only 6% for personal vehicles, although risk perception behaviors varied based on many factors including socio-demographic variables, health conditions, built environment, virus spread, and travel behavior. To reduce this fear, enhance public transit’s reputation in light of COVID-19, and increase riders’ comfort levels, public transit agencies can continue to develop evolving safety practices and cleanliness standards that respond to current health recommendations and public concerns. Additionally, advertising campaigns have also proved effective at improving public transportation’s reputation and supporting ridership, such as Fort Worth Trinity Metro’s “We Got You!” video and digital advertising campaign to increase ridership and build customer trust in the face of COVID concerns.
Park-and-ride lots are strategically located near roads widely used by commuters and are often near transit stations. These lots are convenient places to meet rideshare partners or switch transportation modes to public transportation. Transportation planners can help commuters take advantage of park-and-ride lots by making information easy to access online. For example, Denver’s Regional Transportation District (RTD) website provides interactive maps of park-and-ride lots and a list with information about fees, parking spaces, and transit connections. “Kiss-and-ride” lots and lanes facilitate the quick transfer to and from public transportation and a waiting vehicle.
A growing number of employers are offering mobility benefits as part of an emerging trend to incentivize or otherwise support employees to explore energy-efficient commuting options. Employee mobility benefit packages may include a variety of options, including free or subsidized transit passes and memberships to micromobility systems. These types of incentives may be also beneficial in counteracting reductions in public transit ridership that have been documented since the start of the COVID-19 pandemic.
Employees may benefit from such programs through reduced commuting costs, reduced need for vehicle ownership, and the ability to reclaim time that would otherwise have been spent piloting a vehicle. Employers may benefit from being in a stronger position to recruit and retain labor talent, reduce investments for private car parking, and project an image of energy consciousness. Employee passes and transit subsidies are effective incentives for corporate decision makers to build mass transit ridership, conserve fuel, and reduce VMT. Employer compensation for transit may have tax benefits. Learn more about such commuting benefits from the U.S. Internal Revenue Service.
Find more information and resources on public transportation from:
- The American Public Transportation Association, providing advocacy, research, technical expertise, workforce development and educational opportunities for their members, including agencies representing all modes of public transportation.
- The U.S. Department of Transportation Federal Transit Administration, which works to enhance America’s public transit systems and provides information about the transit-related items in the Bipartisan Infrastructure Law.
- The TransitCenter, a foundation that works to improve public transit in cities across the U.S. through research, advocacy, improving agency practice, and grants.
- The National Alliance of Public Transportation Advocates, which provides resources and tools to support public transit use.