Los Angeles residents have been debating a recent proposal to implement congestion pricing around the region’s most congested area, as London, Stockholm and other cities have successfully implemented.

The idea is straightforward: charge drivers to enter the congested area during peak commute times.  The tolls will discourage extraneous trips and encourage people to drive during off-peak times when they can. Traffic then falls within the tolled area.  Meanwhile, the money raised can support transit investments there.

Larry Mantle’s AirTalk program on KPCC recently explored the proposal in a segment with UCLA professor Mike Manville and journalist Felix Salmon. Manville has conducted important research demonstrating that congestion pricing doesn’t necessarily hurt poor people disproportionately, as critics of the policy often allege.

Manville made a strong case for congestion pricing, but he got tripped up by a caller and Mantle when he argued that right now drivers use the roads for free.  They pointed out that gas taxes and other fees help pay for roads, so they’re already paying for them.  Manville instead argued that nobody pays for using the space on the road, which is a nuanced point.

The problem, politically speaking, is that people are going to recoil being charged for using something that 1) they previously used for free and 2) they feel they already pay for through other fees and taxes.  The policy proposal will be vulnerable as a result, unless backers can describe how the additional fee or toll will give them a specific benefit. In this case, the benefit is reduced congestion.

Perhaps a better framing question would be: how much would you pay per car trip to avoid being stuck in traffic?