Study: Car-sharing squeezes carbon emissions
About 560,000 US residents are members of a car-sharing service, a market that has been growing steadily in recent years including my household — which joined last year. Car-sharers could reach, under the most optimistic scenario, 20.3 million people, according to a RAND Corporation study.
A more likely outcome is for car-sharing to top-out at 7.5 million members, RAND says. Under the most optimistic case, as Streetsblog reported, greenhouse gases from US cars would be reduced 1.7 percent. The more likely scenario would cut emissions by 0.6 percent. That doesn't seem like a huge number, as the Washington Post noted:
For the most part, the people who sign up for car-sharing services were barely driving anyway. On average, Americans who use these sharing services see their car ownership numbers drop from 0.47 cars per household down to 0.24 cars per household. In other words, they went from barely owning cars to… barely owning cars. In contrast, car ownership for the country as a whole is about 1.87 vehicles per household. That’s one reason the effect on climate pollution is so small.
There are two reasons that car-share members drive less to begin with. Many of them are college students, and virtually all of them are residents of walkable communities. But college students graduate, get jobs, and drive more. If they continue to car-share, though, the car-sharing may prevent more driving than would be indicated by this study.
That they all live in walkable communities is a given. Car-sharing doesn't work outside of compact, walkable urbanism. If enough people can't walk to the car, it makes little economic sense to share it. Here's the map for car-sharing in Ithaca, New York, and note that all cars are within the city and reachable on foot.
Ithaca Carshare, which runs the service, has tried putting a car in a more suburban location, but it just didn't get enough use.
People who live in walkable cities already drive substantially less. But car-sharing makes city living more appealing and affordable. It increases mobility for city-dwellers and lowers transportation costs.
I know that from personal experience. We were a two-car family in a city neighborhood. We rarely drove the second car, so it cost us only about $2,000 a year from maintenance, insurance, gasoline, and other expenses. Essentially, it was a convenience. Since we got rid of that car and car-share has become our "second car," we've eliminated nearly all of that expense.
Car-sharing also reduces congestion, pollution, and demand for parking. Off-street parking infrastructure such as surface lots, structures, driveways, garage doors and entries is a major cause of urban dead-zones.
Nearly half of the space in some downtowns is devoted to parking. If, due to the introduction of car-sharing and other changes, much of this land could be redeveloped, many more people could live an urban lifestyle. Whether they are car-sharing or not, they will be driving considerably less and reducing greenhouse gas emissions.
Even better, they will be living in a more appealing city. The less off-street parking is required in a city, the more appealing the urban environment and the more space for things that make communities livable — like residential and commmercial buildings that bring more people downtown.