City Planning Promotes Car-Sharing, But Will It Reduce Driving?

WSJ_Car_Sharing_Graphic.gifCar-sharing is already a part of New York’s transportation system, but new DCP regulations could allow it to spread much faster. Graphic: WSJ

Last week the Department of City Planning announced an initiative to promote car-sharing in New York City. The new zoning amendments remove some of the uncertainty for car-share companies by spelling out where shared cars can be stored. At a hearing on the proposed changes last Monday, one member of the planning commission suggested an additional step with big implications for livable streets — tying car-share to reduced parking requirements — but the planning department has declined to draft rules that go that far.

The promise of car-sharing lies in its potential to reduce car ownership rates. National studies show that between 6 and 32 percent of car-share users give up a car, according to Steve Johnson, the City Planning staffer in charge of the project.

Car-sharing also reduces incentives to drive compared to car-ownership. While the costs of owning a car are largely fixed — you’ve spent a bundle of money on the car already, so driving to the store doesn’t cost much more — the costs of a shared car are tied almost entirely to how much you drive. "When you’re paying by the hour, you drive more efficiently, because you can see the costs associated," Johnson told the City Planning Commission at the hearing.

Data specific to New York City are not available, but according to research by UC Berkeley professor Robert Cervero, car-share members in San Francisco significantly decreased their total driving compared to a matched control group.

If car-sharing reduces car ownership and driving, it could play an important role in a sustainable transportation system. Car-sharing "could revolutionize the desire to own cars in New York City," City Planning Commissioner Amanda Burden said at the hearing. The obstacle to further implementation, she said, is that "there isn’t clarity about where these cars can park." The current zoning text, written in 1961, leaves too much uncertainty about where shared cars can go, which makes it more difficult and expensive for car-share companies to expand. 

The new regulations would set precise conditions on how many off-street spaces could be given over to car-sharing companies in lots across the city, ending that uncertainty. The regulations won general approval from the ten planning commissioners in attendance. Commissioner Karen Phillips, former CEO of the Abyssinian Development Corporation, offered an intriguing additional suggestion: using car-sharing as a lever to reduce the cost of building affordable housing by lowering parking requirements.

If each shared car is used by 40 people, she reasoned, you could build many fewer spaces than parking minimums require while making the option of driving available to the same number of people. That would reduce costs and allow more affordable units to be built on a given lot. 

Howard Slatkin, DCP’s deputy director for strategic planning, offered a litany of objections as he explained why Phillips’s suggestions hadn’t been included in the department’s proposal. You can’t use car-sharing to reduce parking minimums, he said, because "at the time you’re building, you don’t know who the customer is" and can’t ensure that a private car-sharing firm will operate at the development. Slatkin also reasoned that allowing shared parking spaces to replace residential off-street spaces would negate the intent of parking minimums — to ensure that building residents have a place to park where they live. That outcome has been shown to induce more driving.

To unlock the full potential of car-sharing, Phillips’s suggestion to use it in tandem with lower parking minimums is crucial. If car-sharing gets members away from car ownership, maintaining parking minimums could effectively undo that progress by creating a glut of newly-available parking. Likewise, if car-sharing allows 40 people rather than one or two to share a parking space, it would be a pity not to use the freed up space for new homes, offices, and public space. Moreover, all of Slatkin’s objections to a vigorous attempt to use
car-sharing to promote sustainable transportation are logistical. DCP should be able to set up incentives to overcome those hurdles, perhaps similar to how many cities give density bonuses to developers who promise to provide certain community benefits.

By helping to expand car-sharing, the Department of City Planning is moving the city one step closer to a more sustainable transportation system. The next step is to pair the drop in car ownership that car-sharing promises with a drop in parking requirements.

  • Larry Littlefield

    Perhaps DOT could set up a program that would dedicate one on-street parking space on a block to car share services if and when a block resident agrees to give up a car.

  • Noah Kazis

    On-street car-sharing came up at the planning commission meeting. Because of things like alternate side parking and snow regulations, neither the car-share companies nor DOT is interested in pursuing it just yet. Expanding off-street is the first step.

  • Pete

    It would be nice if car-sharing wasn’t lumped in with car-rental when it comes to city taxes. That $11/hr zipcar rental quickly turns into $16/hr once you factor in the city/state fees.

  • Toronto has used a parking reduction ratio of betweehn 10:1 and 4:1 for new condos over the last 4 years. (ie for every shared car onsite, developers have been able to reduce requried parking)

    This study last fall for the City of Toronto also recommended to continue this practice.

  • Larry, I already don’t have a car. They can have my spot.

  • LB

    As an interesting point of reference, the City of Vancouver (BC) allows parking relaxations if a car share parking space (and car) are provided:

  • We are interested in pursuing two goals which don’t necessarily move in concert: reducing car ownership and reducing VMT (miles travelled).

    Car-sharing has the potential – which is the banner that DCP is flying – to reduce vehicle ownership. As noted above, though, DCP is not interested in promulgating rules to strengthen the likelihood of this desirable outcome.

    But a shared vehicle is also more likely to be driven more than a vehicle owned by an individual. That is in one sense a desirable efficiency. If we don’t significantly lower the rate of car ownership, though, we’ve actually increased overall VMTs.

    Here’s the basic question: are the people signing up for car-sharing giving up their personal vehicles or choosing to not buy a car, or are they people who would otherwise be taking the subway or train or bike but see car-sharing as a cheap entry to car ownership? If the city is selling this proposal on its benefits while avoiding steps to ensure the positive outcome, then we should be skeptical.

  • Car Free Nation

    Car sharing is one of the many tools that one can use to not own a car in the city, along with protected bike paths, reliable public transportation, reliable car-services, and resources within walking/biking distances. In our case, the fact that car-sharing was available made it easier for us to get rid of our car.
    But once we got rid of our car, we found that car-sharing was not as necessary as we had thought. We hardly ever use it; instead we bike/walk more and use car-services.
    I’m pretty sure that our experience is not unique.

  • Boris

    Slatkin sounds like an idiot, but I guess you already know that.

    “at the time you’re building, you don’t know who the customer is”

    This argument is totally nonsensical, because you do know who the customer is. Zoning regulations assume that any customer is a driver, which is why any new building must have parking. Duh.

    “[you] can’t ensure that a private car-sharing firm will operate at the development”

    A poor neighborhood also can’t assure it has a supermarket with fresh fruit and vegetables, forcing people to shop at convenience stores with a limited selection. Very little has been done to change that, and there is no government-subsidized alternative. But in the case of transportation, there is an alternative – buses and trains.

  • J:Lai

    Owning a car involves a high fixed cost (cost of the vehicle, registration, insurance, and parking), but the marginal cost of each mile driven is very low. This is known to lead to over-use of the car even when there are good alternatives to driving.
    Car sharing basically flips this relationship around, so you have close to zero fixed cost, but relatively high marginal cost. While this may lead some people to travel by car who otherwise would not (people who do not own a car), it also has the effect of making car trips more expensive. This should lead to decreased demand for car use for trips where there is a competitive alternative.
    For example, we might expect an increase in the availability of shared cars to lead to fewer trips in and out of the Manhattan CBD due to the prevalance of competitive transit options, but more trips that start and end in outer borough locations that are not well served by transit.
    Even if there is no net decrease in VMT, it would still be a good outcome to shift car traffic away from the most congested regions. Although I do believe it would lead to an overall drop in VMT as well.

  • Peter Smith

    only a semi-related question — if you rent a car from a car-share, do you have to return it to the spot you got it from?

    just wondered if it was like bike-sharing programs in that regard. and, i’m guessing even bike-sharing programs have different policies/fees associated with not returning a car to its original spot.

  • lb

    Peter – you do have to return car share vehicles back to their ‘home’ parking spots.

    There is a car share program out there that allows you to leave the car parked anywhere in the service zone when you’re done with it: That’s still just over in Europe though.

  • Larry —

    I was thinking today about how you won’t answer my implied question of why you think the people who own a car are entitled to a free parking spot while the people who don’t own one aren’t.

    This led to my new permit parking plan (which I will boldly reveal in this 2-week-old comment thread):

    Everyone who parks a car on a given block makes a direct cash payment to everyone who doesn’t. The amount is adjusted quarterly so that there are enough spots for everyone who wants one.

    Everybody’s a winner!


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