How much does car-sharing benefit the environment?

A new study investigates local and global effects of car-sharing, finding that the service benefits users and their communities.

From less congested roads to cleaner skies, car-sharing is delivering on community-wide benefits, a new study finds.

A working paper from the University of California, Berkeley's Transportation Sustainability Research Center (TRSC) examined Car2go, the world’s leading car-sharing company, in the first-ever impact study on one-way car-sharing in North America. The take-away: Car2go users decreased their greenhouse gas emissions 10 percent on average, and eased the commutes of non-users by eliminating cars from the roads and parking spaces. 

The transportation sector is a focal point in the push for cleaner skies, as transportation emissions accounted for more than a quarter of US emissions in 2014, according to the Environmental Protection Agency. Cities are leading the way in rolling out innovative transportation solutions, including car-sharing, which is expected to see revenue grow from $1.1 billion to $6.5 billion between 2015 and 2024.

“Our exhaustive, three-year research effort into one-way car-sharing reveals that Car2go vehicles result in fewer privately-owned vehicles on the road, fewer vehicle miles traveled, and a reduction in greenhouse gas emissions,” Susan Shaheen, who co-led the study, said in a press release.

Car2go has nearly 2 million members who share 14,000 vehicles in 30 cities. Users have access to the shared fleet of vehicles, which they can locate on an app and drop off at their destination anywhere within an urban zone, or sometimes at a designated parking station. Drivers typically pay per minute in the car, with discounted hourly and daily usage options available. 

Across the five cities studied – Calgary, San Diego, Seattle, Vancouver, and Washington, D.C. – Car2go was responsible for 28,000 fewer vehicles on the roads, says the report, since each new Car2go car eliminated the need for seven to 11 vehicles.

Of the 9,500 Car2go members surveyed in the five cities, between two and five percent sold a vehicle because they had access to the car-sharing service, and another seven to 10 percent said they dropped previous plans to buy one. 

Fewer cars getting purchased has an environmental benefit of its own, since approximately one-fifth of the emissions a car releases during its lifespan are caused during production.

TSRC researchers hope to pave the way for better-informed public policy decisions, Dr. Shaheen told the Vancouver Sun, "to help decision-makers who are faced with a whole range of innovative strategies to help provide greater mobility and access to their citizens."

If cities want to set aside scarce public parking spaces for car-sharing services, for example, they need to be able to estimate the payoffs.

Shared cars tend to be smaller and newer than those in the average household, according to Intelligent Energy Europe. Newer vehicles are more fuel efficient, reflecting technological upgrades, plus car services allowing people to select the car appropriate for their journey: a two-seater for a quick jaunt to the beach, but an SUV for a family weekend trip.

A twist on the typical car-sharing service is catching on in Chicago, capitalizing on the fact that vehicles sit idle about 95% of the day, on average. Gataround, a peer-to-peer carsharing service that calls itself an AirBnB on wheels, allows people to rent out their cars to drivers in the area who want a quick trip, as The Chicago Tribune reported. Renters and owners in the Chicago area have more than doubled from 8,000 to 20,000 since the program's launch a year ago.