RAND: Car-Sharing Could Cut Carbon Emissions From Cars By 1.7 Percent

Source: RAND Corporation

The brilliant thing about car-sharing is that it leads people to drive less by providing access to cars. It allows people to give up their personal vehicles (along with the gas, maintenance, parking, and insurance costs they entail) without giving up the ability to use the car once in a while when necessary. It diminishes the need for parking spaces, since one vehicle can serve several households. And it makes people think harder about the trips they take, since each trip constitutes a higher cost than in a personal vehicle, which come with high upfront costs but low per-trip costs, encouraging more driving just to get your money’s worth out of your investment.

But only 0.27 percent of U.S. drivers participate in car-sharing programs.

A recent study from the RAND Corporation estimates that that number could rise to 4.5 percent if policies were put in place to support car-sharing. RAND’s outer estimate of the potential of car-sharing goes as high as 12.5 percent of the 21-and-older population of major cities. The potential for greenhouse gas emissions savings is significant.

The RAND authors cite a 2008 survey showing that for every shared vehicle in use, nine to 13 private vehicles are taken off the road, and that half of car-sharing participants either sold a car or didn’t buy a new car because of their membership. Another survey found that average vehicle ownership per household fell from an already-low 0.47 to 0.24 cars after adopting car-sharing. Average vehicle ownership per household is 1.87 in the United States.

RAND attributes the greenhouse gas reductions from car-sharing to a) fewer vehicle miles traveled, b) fewer cars being manufactured, and c) more efficient vehicles being used more of the time. After all, car-sharing can avoid SUV syndrome, where people buy a big, heavy car for the one time a year that they actually go into the mountains with it, and then spend the rest of the year driving alone on highways and trying to park it in small spaces. Also, intensively-used shared cars will be replaced more often than private vehicles, meaning that more of them will have the most modern fuel-efficiency ratings. The report doesn’t mention the GHG savings if car-sharing results in the building of fewer roads or parking spaces.

The estimates of car-sharing’s potential market penetration are among the most helpful elements of the RAND report.

In the most optimistic scenario — 20.3 million car-share users, or about 36 times the current rate — car-sharing would reduce overall car emissions by 1.7 percent. A more realistic scenario of 7.5 million users, which would still require the widespread adoption of policies to support car-sharing, leads to a 0.6 percent emissions reduction. The authors provide a “cautionary note that estimates of growth in vehicle sharing have previously been proven wrong.” They cite a 1994 study that predicted that the market potential in Germany was 2.45 million members; “however, ten years later, the market stood at 70,000.”

On a per-person basis, car-sharing doesn’t cut emissions as much as transit. One person taking transit to work instead of driving can save more than two metric tons of carbon dioxide emissions a year, according to APTA, as opposed to the above estimate of 0.89 tons per person car-sharing. But car-sharing also works in tandem with transit, functioning best where people can rely on transit for many trips. Car-sharing remains a largely urban phenomenon, according to the RAND report, with the only non-urban success stories on college campuses or eco-communes.

The other major contribution of the report is that it suggests some ways to make car-sharing more attractive. They say it will never take off unless car-sharing is 1) cheaper and/or more convenient than owning a personal automobile, 2) profitable for providers, and 3) reaches critical mass in a geographic area. To make that happen, they recommend reducing impediments in insurance policies and tax codes and increasing provisions for “one-way, dynamic vehicle sharing,” and better ride-matching services. The recommendations also include the promotion of short-distance, low-speed “neighborhood vehicles,” like the golf carts senior citizens drive around retirement communities, and the promotion of driverless vehicles. The report doesn’t explain in detail how driverless cars would enhance vehicle-sharing.

  • fj

    Yep, car-share saves something; but, the one time I used it, it was awful since I am used to cycling around for virtually everything and the difficulties and potential danger using a car was nightmarish — cost also — and way outside my comfort zone; and, something that I’d use only as a last resort.

    Cycling and net zero mobility rules!, and people should really start focusing on net zero methods and apparatus for traveling about and forget about cars.  Cars do not fit in the future.

    Just like Mao was probably responsible for the deaths of tens of millions with his bad ideas about land reforms, etc., the same goes for the current regime advocating heavy machinery transportation like cars, buses, trains, instead of very small light vehicles that can easily be powered by human power; though, potentially also by small fractional horsepower electric motors as well.

    And, it makes absolutely no sense to consider moving the still existing one-half billion Chinese cyclists to transportation systems based on cars instead of advanced systems based on net zero vehicles.

  • Andy Chow

    I think that driverless vehicles could enhance sharing by having the ability to maneuver the vehicles to meet demand. Think of the scenario where there’s a strong one way demand in car share. Unless the vehicles are moved to where the demand is, then there would be enough vehicles made available. The rental car industry hires a lot of people just to drive cars between the rental car locations.

  • Urban Reason

    I think car sharing is great, but personally I can’t see it being very relevant or pervasive in Los Angeles until autonomous vehicles start hitting the streets in the next few years. When we can summon a vehicle from a ‘car-sharing’ subscription service on our iPhones that doesn’t require a driver or a license – I can see a lot of things changing.

  • JamesR

    Urban Reason, I wouldn’t hold my breath for autonomous vehicles any time soon.

  • Andy Taylor, AICP

    I compare this to what David Owen, in _The Conundrum_ writes about Farmers’ Markets. Local food actually creates some carbon emitting, energy inefficiencies. The best part about local food and farmers’ markets are that they make urban, dense, energy efficient areas more livable — and that’s where the true energy savings, carbon emission reductions are. I’d imagine that car sharing, in the long run, can have a similar impact.