There's talk now of tolling our freeways to reduce congestion. What about a time-tested solution: HOV lanes? Seattle and the Bay Area use them everywhere. We only have one, on Interstate 5 northbound in North Portland. What gives? —Donna N.

It's true, our only HOV lane is that one on I-5. And at 3 pm, when the left lane goes HOV and all the single occupancy vehicles, or SOVs, have to merge into the two right lanes, you can actually watch the afternoon traffic jam freeze in place, like a snowflake forming under an electron microscope.

I am not saying this proves HOV lanes make traffic worse. But it does suggest that doing something similar with, say, Highway 217 is going to be a pretty heavy lift politically, especially with the motorists who are going to get squeezed into the remaining lanes.

"Well, serves them right!" I hear you saying. "They should carpool!" This illustrates both the appeal and the futility of HOV lanes: They're popular because they ostentatiously punish something we consider environmentally irresponsible (SOVs driven by people who aren't us), yet they self-evidently fail to elicit the behavior (carpooling) they were designed to induce.

Think about it: If HOV lanes actually performed as advertised, tons of people would be carpooling by now, and the HOV lane would be as congested as every other lane.

"Ah!" you say. "But there would be fewer cars, meaning at least a bit less congestion and fewer vehicle miles traveled overall, saving the planet!"

Putting aside the fact that a crowded HOV lane presents zero incentive to carpool, a UC Berkeley study of Bay Area traffic showed HOV lanes actually worsen congestion by 21 percent. The SOV lanes get congested because of the extra traffic, while the HOV lane itself gets blocked by so-called "snails," slow drivers, becoming a one-lane highway where no one can pass.

I think it would be interesting to see what would happen if the powers that be suspended the HOV restriction on that stretch of I-5 for a week. It certainly seems like HOV lanes are an ebbing tide that lowers all boats, tolerated only because they appear to lower the less popular boats even more.