I don’t often agree with New York Times columnist John Tierney, but on this I do. The idea of opening up HOV lanes to hybrid cars is getting bandied about quite a bit, and is already a reality in Virginia and California. But as enticing as the idea may seem, I think it’s a mistake.

In Virginia, carpool lanes are getting more and more clogged with drive-alone commuters in hybrid cars. But in terms of saving energy, it’s more important to keep HOV lanes flowing freely for transit, vanpool, and (perhaps) carpools than to fill them with drive-alone commuters — even if they’re driving efficient cars. As more and more hybrids enter the vehicle fleet, the HOV-clogging problem will only intensify. Plus, hybrid owners may quickly come to perceive driving in the HOV lane as a right rather than a privilege, making it harder to reclaim those lanes for transit. On top of all that, politicians have a disturbing tendency to lower standards, allowing bigger and less fuel-efficient hybrids to use the lanes. So it’s a bad idea to begin with, and the slippery slope makes it seem worse and worse.

Turning HOV lanes into HOT lanes — "high-occupancy/toll" lanes free to buses and carpools, available to others for a toll that’s dynamically priced to keep traffic flowing — is a better option than opening HOV lanes to hybrids. Both ideas increase the number of cars on the road, but HOT lanes at least have the advantage of keeping transit moving smoothly while introducing the not-so-radical notion that freeways aren’t really free.

The most potent argument against HOT lanes is that they’re really "Lexus Lanes" — i.e., rich people will pay to use them but everyone else will be stuck in traffic. Admittedly, the optics of HOT lanes aren’t great. But hybrid owners tend to be a well-heeled bunch too, so giving them free access to the HOV lanes still has social and class implications. And besides, according to this Q&A (scroll down to the bottom) studies of HOT lanes in California say that:

Although roughly one-quarter of the motorists in the toll lanes at any given time are in the top income bracket, data demonstrate that the majority are low and middle-income motorists. The benefits of the HOT lane are enjoyed widely at all income levels.

I don’t take that as definitive — but it certainly suggests that the well-off wouldn’t be the sole beneficiaries of HOT lanes.