The emergence of ride-hailing services may be placing a small dent in car-ownership in some parts of the country, but don’t count on Americans to shed their personal cars in any significant way, anytime soon.   “The short answer is people are just as attached to cars as ever,” said David King, one of the authors of a new report, Trends in Taxi Use and the Advent of Ridehailing, 1995–2017: Evidence from the US National Household Travel Survey, by the School of Geographical Sciences and Urban Planning at Arizona State University. “There are some studies that have found a small reduction in car ownership due to these services, but these are ‘marginal’ auto owners to begin with.”   This is certainly not to say ride-hailing, car-sharing, bike-sharing and other forms of mobility services are not posing a “disruption” — to borrow the parlance of Silicon Valley — to the transportation landscape.   Transit agencies in a number of cities have explored or initiated plans to partner with transportation network companies (TNC) — as Uber and Lyft are known — or outright mimic them. While city planners are pondering how to accommodate so many cars picking up and dropping off passengers, parking officials have begun planning for reduced revenue in a world where Uber and Lyft are increasingly pervasive. Whether these new mobility services have truly quenched Americans' appetite for purchasing and driving their own cars is still up for debate, however.   “There was some data, maybe like five years ago, that younger people were postponing drivers' licenses and things like that,” said Jon Orcutt, director of communications and advocacy for the TransitCenter. Orcutt is the former policy director for the New York City Department of Transportation. “But car-ownership is not going down, as far as we can tell. And it certainly hasn’t gone down in New York, even with the explosion of Uber and Lyft.”   Still, there is some speculation that ride-hailing services could lead to reduced car-ownership. The ASU report cited a survey in Austin, Texas, where 9 percent of ride-hailing users said they purchased a vehicle when the city’s voters took steps in 2016 to regulate TNCs much like taxis, all but driving Uber and Lyft out of town. (The two have since returned, following action taken by the state Legislature.)   But generally speaking, when a household sheds a car in lieu of using a ride-hailing or car-sharing service, it’s usually a second car, said King.   A January 2018 report by the Southern California Association of Governments actually pointed to an increase of car-ownership as a leading reason for the decrease in transit ridership in the Southern California region.   Indeed, if the roads seem more crowded, they are. The total vehicle miles traveled in the United States in 2017 increased 1.2 percent from the year before, continuing an upward trend going back to at least 1992, according to U.S. Department of Transportation statistics.   The views of officials from the transportation technology industries are also mixed on the degree to which personal car ownership is declining.   “I think it is too early to say car ownership is declining, though if you talk to high school and college students, it seems like there is much less urgency on their part to learn to drive, much less get a car,” said David deKozan, vice president of business development at Cubic Transportation Systems. “In the long run, it would seem likely that we will see fewer multi-car households and more people living close to transit hubs.”   The ASU report noted, “2017 transit users are also more likely to be ridehailing users, all else equal,” but was careful to add, “this does not necessarily mean that transit ridership will increase as ridehailing use increases.”   Researchers have found that “some” ride-hailing trips would be taken on public transit if the ride-hailing option were unavailable.   “But this does not necessarily mean that transit ridership will drop as ridehailing use increases,” according to the ASU study. “Ridehailing can compete with transit for individual trips while still complementing transit as a part of a low-car lifestyle.”   As transit becomes “redefined beyond rail and bus services,” and morphs into an integrated network of ride-hailing, car-sharing, bike-sharing and other mobility forms, it will be positioned to experience increased ridership, said deKozan.   Amos Haggiag, CEO of the transit operations platform Optibus, pointed to several university studies that anticipate reduced car-ownership trends in the wake of Uber and Lyft. However, he added, “we don’t know yet.”   “In general, car ownership is lower when the costs of owning a car are high — think Manhattan parking and traffic — and when public transit works well, making the idea of using a car less tempting,” said Haggiag. “So, while the future of e-hailed or shared autonomous cars seems interesting, it is quite certain that they will be used for portions of trips, where mass transit is used for the ‘core’ of the trip.”   The issue of how car-ownership might shrink amid ride-hailing prompted AAA, the gold-standard of car-club member organizations, to offer its own advice to consumers, which said, in short, buy a car.   AAA researched the cost of ride-hailing in 20 U.S. cities like Nashville, Atlanta, Miami, Los Angeles and New York, and found that the average cost of ride-hailing would reach $20,118, annually, if this were the only mode of transportation. The car club assumed both car owners and those without cars, using ride-hailing services, would both travel 10,841 miles per year.    In comparison, the average annual cost of owning and operating a personal car is $7,321 for 10,841 miles of travel annually, according to AAA.   But this view may not take in the whole transportation picture, according to Orcutt.   “The places where these [ride-hailing] services are used intensively, the trips are shorter,” he said. “So, the mileage wouldn’t be comparable. And yes, people have more options. So they use transit. They walk a lot. And they just have a variety of ways to take like, the several-mile trip that is typical.”   Regardless of AAA's methodologies, its study is a measure of the impact ride-hailing is having on transportation and how it's attracting attention from a range of observers.   “We can't guess the motives for the AAA study,” said Haggiag. “Regardless of the reason, it seems that the topic is receiving a fair share of attention since it highlights the fact that cars — and bikes — lie around, completely unused, when people are not using them.”   “Whether you own a vehicle or not, ride-hailing services are a convenient transportation option,” said John Nielsen, AAA’s managing director for Automotive Engineering and Repair, in a statement. “However, with the average American city-dweller driving nearly 11,000 miles per year, a personal vehicle is still the more cost-effective choice.”   “For those who travel a very limited number of miles annually, or have mobility issues that prevent them from driving a personal vehicle, ride-hailing can be a viable and important option,” continued Nielsen. “But, for everyone else, the car is still king.”   The National Household Travel Survey found that about 10 percent of Americans have used a ride-hailing service in the last month, with higher use in urban areas and among higher-income earners.   To be sure, there is no shortage of chatter around ride-hailing and other emerging mobility options, numerous studies and reports have shown. How much these services are truly upending transportation is still an open question, say observers.   “What’s kind of remarkable is how much of the transportation discourse it’s taken up, relative to its actual presence on our roads,” said Orcutt.   In fact, for-hire vehicles account for 0.5 percent of all trips taken in the United States, according to the ASU report.   “I just think there’s kind of a hype machine and kind of a debate momentum, or sort or a rhetorical momentum around these things,” said Orcutt.   “If you look around city governments right now, they’re all debating Bird Scooters, right? Which is like, zero transportation footprint, absolutely zero transportation footprint. And everybody is stampeding about what their policy is on these things,” he added.    “They’re not going to make a dent in, like, Boston, or anywhere else, unless you have maybe 20,000 of these things or more,” Orcutt continued. “So there’s this very strange sort of rhetorical phenomenon where everyone’s talking about all this stuff that is really only having certain impacts.”