Last month, the ride-hailing company Lyft released its vision for the future of Los Angeles. In a meticulous rendering depicting Angelenos of all ages and races and species (some are dogs), Lyft shows off a city that’s greener, healthier, and more walkable. The 10-lane Wilshire Boulevard, one of LA’s clogged east-west arterials, now has separate space for cyclists. Driverless buses operated by LA Metro pilot down their own, traffic-free lanes. And shared driverless cars—operated by a futuristic Lyft Line service, probably—ease on down the road.
For these city-dwellers, there’s no need to buy (or maintain) their own vehicles. Shared rides mean fewer cars mean less traffic mean less pollution mean—finally, in the end—a happier American city. There’s a lot to love about this Lyft picture.

But this is not the way these ride-hailing services have played out, not yet. According to a new, multi-city study by researchers at the University of California, Davis, ride-hailing companies like Uber and Lyft might not be taking cars off the road at all. The work is based on 4,100 online surveys distributed to a sample of Americans in seven big metros: Boston, Chicago, New York, Seattle, San Francisco, Los Angeles, and Washington, DC. The respondents are a mix of urbanites and suburbanites, and they answered the surveys between 2014 and 2016. Through their responses, the shifty picture of the modern, ride-hailing-packed city is beginning to snap into place. It might have more cars, not fewer.
First, ride-hailing service users aren’t necessarily getting rid of their personal vehicles. This has been some matter of controversy for researchers, because it’s hard to figure out whether the services' more enthusiastic users sold their cars or never had cars at all. According to this self-reported data set, it’s more often the latter: 91 percent haven't ditched their vehicles.

That lines up with prior research, mostly. According to a small Reuters/Ipsos poll, a quarter of Americans got rid of their old cars last year, and 9 percent of them decided to forgo a new one in favor of ride-hailing services.
It’s harder for these researchers to pin down whether ride-hailing services have enabled people who don’t own cars to stay that way. Did they choose not to buy a car in the first place because they knew Uber existed? Data on people ditching their vehicles wouldn't pick this up. If researchers could get a cleaner grasp on those numbers, they could more definitively figure out if Uber and Lyft have added more cars to the road, or subtracted them.

Second, companies like Uber and Lyft haven’t necessarily put a dent in the number of miles traveled by car in cities overall. In fact, the UC Davis researchers found that 49 to 61 percent of ride-hailing trips wouldn’t have been made without those services to provide them. That means Uber and Lyft might not be taking fossil fuel-puffing cars off the road. They could be adding them on.

“It doesn’t matter who owns the vehicle,” says Regina Clewlow, a transportation researcher with UC Davis who worked on the report. “It matters how many miles are driven on the road. So me swapping out a trip that I would have driven myself for a trip that I’m riding in is still the same number of miles.” In fact, she points out, it could be more, thanks to the time your Lyft driver spends zooming to neighborhoods with surge pricing, or idling about while waiting for fares. More time on the road means, potentially, more time for a car to release carbon emissions, or to get into a crash.

Extrapolated way out, this research looks more dystopian than friendly-Wilshire Boulevard-in-the-sunshine. Uber and Lyft could be contributing mightily to traffic. They could be choking downtowns with fumes. They could be helping, incrementally, to move affluent riders from public transit systems to privately driven cars.

But we definitely don’t know those things for sure. The researchers in the UC Davis study don’t know when ride-hailing trips are happening, so they can’t say whether they’re contributing to traffic. Their work doesn’t explicitly measure air effects. (Uber pledged to shift all its London cars to hybrid or electric by 2020). And, critically, the report doesn’t account for the existence of UberPOOL and Lyft Line, the ride-sharing services that group together passengers riding in the same direction. If most of these trips are happening in cars packed with three or four passengers, that could reduce the total number of miles traveled by car. Carpools, in other words, rule.
But added to the pile of work amassed by other researchers in the past half-decade, the study does give big cities a clearer sense of how ride-hailing services play out on their streets. According to this and other research, ride-hailing does reduce incidents of drunk driving. In some cases—but not all—it competes with public transit. In some cases—but not all—it adds cars) to the road.
If cities don’t like parts of those realities, they have some options. Congestion pricing would charge motorists to enter certain parts of cities in certain times of day, temporarily hiking up the price of an Uber ride and limiting them to those who really need it. That would solve some traffic problems.
Deals with public transit agencies could complement public transit, instead of competing with it. These are especially welcome in smaller cities or sections of cities without robust public transit, where Uber and Lyft can fill gaps. The companies have run pilot programs in Florida, Colorado, and Canada to get residents to nearby transit, or to replace public trains and buses altogether.
And cities could get better about collecting their own numbers, and about requiring private companies to disclose specific kinds of data in exchange for a license to operate. "One of the challenges as a transportation researcher today is that a lot of the best data is locked away in the private sector," says Clewlow. "It’s really difficult for city and transportation planners to understand what’s happening. Cities need to be proactive about collecting their own information."
Uber and Lyft say they want to help cities change. "We, along with global experts on this issue, believe that the future of urban transportation is going to be a mix of public transportation and ridesharing," an Uber spokesperson said in a statement. "We believe our cities need more efficient, affordable transportation options to make car ownership a thing of the past and look forward to continuing to work collaboratively with transit agencies to achieve this goal," Lyft said.
Which means if anyone really wants that pretty picture of a future Wilshire Boulevard, they need to get to work.

RIDE-HAIL RULES

• Lyft is really is working on self-driving cars—and soon they’ll be driving around San Francisco
• Uber hits a pothole as London yanks its operating license
• Maybe Uber’s new CEO, Expedia vet Dara Khosrowshahi, can sort it out