Ride-hailing services could be making pollution worse, research finds

Ride-hailing fleets hold the potential to someday reduce the amount of pollution collectively spewing from cars.

In all likelihood, however, they're making matters worse. All while weakening public transportation.

That's according to new research that puts fresh perspective on the way ride-hailing reshapes the transportation landscape.

There is some promising news. Researchers at Carnegie Mellon University simulated replacing private vehicle travel with ride-hailing services across six U.S. cities. Because vehicles emit more pollution during "cold starts" and because ride-hailing vehicles tend to be newer, this swapping, as simulated, could spur a 50 to 60 percent decline in emissions.

But there's a practical downside: Ride-hailing vehicles create about a 20 percent increase in fuel consumption and greenhouse gas emissions because of "deadheading," the miles driven without paying customers.

That augments findings from MIT and Harvard researchers, who wrote this month that even fleets of all-electric robotaxis would not reduce pollution and, in some cases, may actually create more pollution.

Beyond emissions, the Carnegie Mellon researchers say overall costs associated with traffic congestion, crashes and noise increase by 60 percent with ride-hailing vehicles. These "externality costs" are tripled when ride-hailing replaces public transportation.

And in the real world, that's happening.

Ride-hailing fleets have "catalyzed a downward spiral in many public transportation systems," according to a separate study released this week by University of North Carolina and University of Michigan researchers.

As more people opt for ride-hailing, public transportation systems are slashing schedules to account for diminished revenue. Before the pandemic, ride-hailing services had already "successfully encroached" on public transit ridership. COVID-19 has destabilized the revenue models for both.

That's "particularly concerning, because it negatively impacts the most vulnerable and disempowered in society," the North Carolina and Michigan researchers wrote.