Ride-hail companies such as Uber and Lyft do not really reduce congestion or pollution in large, dense cities such as Boston, according to a new analysis from consultant Bruce Schaller.

About 60% of ride-hail car users in “in large, dense cities would have taken public transportation, walked, biked or not made the trip,” Schaller writes in “The New Automobility: Lyft, Uber and the Future of American Cities.”

Basically, it works like this: Uber, Lyft, et al put 2.8 new vehicle miles on city streets for each mile of personal driving they take away. Such a 180 percent increase in urban driving undercuts two of the prime arguments that ride-hails often employ.

One argument is that the ride-hails ease congestion—and therefore pollution—in cities by taking drivers off the road. The other is that the companies complement mass transit by providing options for shorter or more out-of-the-way trips, including via carpooling functions.

Boston-area residents and visitors are certainly taking advantage of the ride-hails. Services Uber and Lyft provided more than 65 million car trips in Massachusetts in 2017, according to state data.

Of those rides, nearly 35 million were in Boston proper, which translates into an average of 96,000 a day—or 67 Uber and Lyft rides underway in any given minute in 2017.

For their part, Uber and Lyft questioned Schaller’s methodology and stressed the congestion-busting potential of their car-pooling functions.