Research gets more robust on potential of shared mobility

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This is an excerpt of an article that originally appeared at Move Forward.

Bikesharing, carsharing, ride-hailing services like Lyft and Uber, and ridesharing in the forms of carpooling and vanpooling are changing how people travel and transforming cities around the world.

Here is a roundup of some of the latest research on the effects of shared mobility across the broader landscape of urban transportation.

Bikesharing

Bikesharing enables on-demand and very low-emission mobility. It also largely pays for itself, with the majority of bikesharing operators covering the costs of bicycle maintenance, storage, and parking from user fees.

Early documented impacts of bikesharing include increased mobility, reduced greenhouse gas (GHG) emissions, decreased automobile use, economic development, and health benefits. Research has shown that public bikesharing typically reduces driving and taxi use, while increasing bicycling in most cities. Another study found that half of all bikesharing members reduced their personal automobile use.

Bikesharing has also been shown to complement and compete with public transit. The difference appears to depend on local factors, but more research is needed. One geospatial study of bikesharing found that shifts toward public transportation in response to bikesharing tended to be more prevalent in lower-density regions on the urban periphery. This indicates that bikesharing may serve best as a first- and last-mile connector in smaller metropolitan regions with less-robust public transit networks.

The counterfindings that shifts away from public transit were most prominent in urban cores suggests that bikesharing may offer faster, cheaper, and more direct connections than short transit trips. Further, bikesharing may be more substitutive in central cities, perhaps providing relief to crowded public transit lines during peak periods.

Carsharing

Carsharing lets individuals enjoy the benefits of using a private vehicle without paying the costs and incurring the responsibilities of ownership. Individuals typically access vehicles by joining an organization that maintains a fleet of cars and light trucks deployed in lots located in neighborhoods and at public transit stations, employment centers and colleges. The carsharing operator typically provides gasoline, parking and maintenance, while participants pay a fee each time they take a vehicle.

Academic and industry studies indicate that carsharing can lead to:

• Participants selling their own vehicles or forgoing second vehicle purchases
• Increased walking and biking
• Reduced vehicle miles traveled (VMT)
• Increased access and mobility for formerly carless households
• Reduced fuel consumption and GHG emissions, and
• Greater environmental awareness.

A study involving multiple carsharing operators found that each round trip in a shared vehicle resulted in an average of 9 to 13 other vehicles being taken off the road. The “missing” vehicles include ones not sold.

Another study showed that roundtrip carsharing had a neutral-to-negative impact on public-transit ridership. Four of five carshare users used rail more, and nine of 10 took the bus more often than they had before. The frequencies of walking, biking and carpooling also increased for carshare users.

The same study on carsharing and other forms of transit also showed that respondents reduced their average annual GHG emissions per household by 0.84 metric tons as a result of not buying vehicles. This represented a 41 percent average decline in GHG emissions per household.

A study that looked at car2go in five North American cities supported most of the findings of the other studies. First, each one-way trip in a car2go vehicle resulted in the removal of an average of 7 to 11 other vehicles from the road, including skipped vehicle purchases. Correspondingly, reductions in GHG emissions ranged from 4 percent in Calgary to 18 percent in Washington, D.C., on average.

Users of car2go vehicles in four cities surveyed did not change their public transit habits. The carshare users did, however, report walking more often.

Ride-hailing

The impacts of ride-hailing on vehicle trips, vehicle occupancy, VMT, GHG emissions, and the use of other transportation modes have not been extensively studied. While one study concluded that ride-hailing replaces more automobile trips than public transit trips, multiple other studies suggest that ride-hailing can compete with public transit, bicycling, and walking.

A survey of ride-sharing service users in San Francisco during the spring of 2014 revealed that 92 percent of respondents still would have made the trip had ride-hailing not been available. This suggests that ride-hailing has an eight percent induced travel effect. Similarly, a 2017 review of studies on the trip-making impacts of ride-hailing services revealed that ride-hailing contributed to a 3.5 percent increase in New York City during 2016.

Looking at Denver, another researcher found that ride-hailing takes more vehicle trips to move fewer people and that vehicles spent longer on the road without passengers. A study conducted by the San Francisco County Transportation Authority reached a similar conclusion. Approximately 20 percent of total ride-hailing VMT were out-of-service miles. While there may be an increase in VMT due to ride-hailing services, the exact magnitude is still unknown and likely depends on local characteristics like density and land use.

Ridesharing

Despite existing for more than 70 years in North America, ridesharing has been subjected to few quantitative analyses. While ridesharing’s costs and traveler benefits remain unclear, the general understanding is that participants experience reduced travel costs, shorter travel times and lower commuter stress.

One study of casual carpooling in Houston found that carpoolers between the ages of 25 and 34 were more likely to make commute trips (96 percent) versus non-commute trips (80 percent). The younger carpoolers were also more likely to be single or married without children than were HOV lane users. More than 60 percent of HOV users traveled with family members.

Another study of casual carpooling in the San Francisco Bay Area before 2010 estimated a total reduction of between 450,000 gallons and 900,000 gallons of gasoline consumption per year. The majority of that fuel savings was attributed to reductions in traffic congestion.

A more recent study of Bay Area casual carpooling published in 2016 revealed that carpoolers ranked convenience, time savings and monetary savings as their primary reasons for participating. Environmental and community-based motivations ranked low. This study also showed that 75 percent of casual carpoolers were previously public transit users, and more than 10 percent formerly drove alone.

Recommendations

To fully assess the impacts of bikesharing, carsharing, ride-hailing, and ridesharing, local governments should consider requiring shared-mobility service operators to share data and report key metrics.

There is also a need for public agencies and researchers to conduct additional studies on the travel, social, and economic impacts of shared mobility.

Photo by A.E. Landes Photography for Mobility Lab.