Peak Traffic

Reader JT says that self-piloted cars that dropped you off at work and then went home “would double our current traffic problems.”

Maybe yes maybe no. I don’t want to get too deep into the issue of what could be done with hypothetical robot cars. But it’s important to recall that our “traffic problems” aren’t really a problem of total road capacity, they’re a problem of peak road capacity. I once left DC at 11:30 PM on a weeknight and drove to Richmond. You’ve never seen I-95 so clear of traffic. And you’ve probably never seen it for the same reason there was so little traffic — nobody drives at that hour. Which is part of the reason why a well-designed congestion pricing scheme can do an enormous amount of good. Relatively small financial incentives aren’t going to compel people to radically reorganize their lives, but they very much can cause people to shift low-priority trips out of peak usage times. That leaves people who really do need to travel at peak times stuck to pay the fee, but in exchange for their fee they get shorter, less annoying commutes. Right now we have roads that are very frequently under-utilized at the same time that most of our trips occur during periods when they’re overtaxed. More transit, etc., is part of the solution to that problem but so is simply spreading the driving around so that somewhat more of it occurs at low-usage periods.