The Digest: It Will Take A Lot More Than Autonomous Vehicles To Unclog City Centers

Downtown traffic is here to stay, at least for a little longer.

ZIPADEEDOO-NAH. Like sitting in traffic? Well, when autonomous vehicles become widespread, you might be doing it a lot more.

A new report by the World Economic Forum (WEF) found that the use of autonomous vehicles could decrease average travel time by four percent in a city like Boston. That's for people who live in the areas surrounding the downtown core — AVs would actually worsen travel times by five percent inside the city itself.

WEF's impact study used a complex agent-based simulation of traffic and "vehicle-to-vehicle interaction" in downtown Boston to arrive at these numbers, including data from roughly two million daily passenger vehicle trips.

AUTONOMOUS TRAFFIC JAMS. But despite the optimism about alleviating Boston's overall traffic woes, the traffic simulation assumed a 20 percent drop in "personal-car trips, which become mobility-on-demand trips" — think Uber, and Waymo taxi rides. And that may sound pretty optimistic, but with decreasing car sales and a booming ride-hailing industry, it's not much of a stretch. Yet 40 percent of trips would still rely on personal vehicles, clogging up low-capacity arteries, and the downtown core. As for mass-transit, the simulation assumed the behavior of commuters wouldn't change.

TEAMWORK MAKES THE DREAM WORK. Unclogging city centers is a complex issue with a ton of moving parts. Replacing all personal vehicles with AVs — including pay-to-go robot-taxi rides — wouldn't have a huge impact on the number of passenger vehicles on the road. As the WEF report points out, policy makers would have to step in and make changes to local infrastructure to truly have an effect on traffic. For instance, policy makers could introduce per-mile tolls for single-occupancy vehicles, use on-street parking to free up some much needed space for bike lanes or loading zones, or dedicate entire lanes just for AVs. And they ran the numbers again, and the results are promising: a per-mile toll could improve travel time by as much as 15.5 percent.

JOINING THE AV CLUB. Autonomous vehicles can offer us more than just (small) improvements to our traffic nightmare woes. They can improve fuel efficiency, and overall reductions in emissions. And then there is the simple fact that you won't have to stare at the bumper of the poor guy in front of you when you're stuck in traffic. You can lean back, relax, and have the car do the driving. Who cares if you have to spend five percent more time on the road?

THE FUTURE IS NOW. Lyft, Uber, and Waymo's AVs are already hitting the streets — private and public — as we speak. The robo-taxi revolution is right around the corner, and there's not much anybody can do about it. General Motors has already released a steering-wheel-less car concept, giving us a pretty good look at what the future of the private passenger vehicle could look like.

But autonomous vehicles alone won't make the gridlock go up in a puff of smoke. Careful considerations of road infrastructure, and investments in mass transit are just as much part of that effort. Only then will we be able to look back and think of how many hours we've wasted every week sitting in bumper-to-bumper traffic.