HOT or not?

I see from this article in the Chron that my impression of the whole HOV-to-HOT lanes thing has been mistaken.

If an HOV lane becomes congested under rules requiring at least two people in each vehicle, there is little choice but to bump that requirement to a minimum of three people. That likely would result in some unused lane space. Why not charge solo drivers to use that space, proponents say, raising the tolls as needed to keep traffic moving?

"Until a lane becomes quite congested with the two-plus requirement, I feel that it should stay at two-plus," [Mark Burris, an assistant engineering professor and research scientist at the Texas Transportation Institute,] said.

Lanes that already are congested under the two-occupant minimum may need to go to a three-plus minimum to remain effective as HOV lanes -- regardless of whether they charge a toll, Burris said.

Any available space then could be used by toll-paying drivers without negating the lane's HOV function, he said.

"On the Northwest Freeway in the afternoon, it's getting to the point where they will have to raise the requirement." Burris said. "There's really no choice if you don't want the lane to slow down."

TxDOT traffic operations director Carlos Lopez said the toll option really could reduce HOV lane traffic, because "It's a lot harder to form a three-plus carpool than a two-plus carpool."

See, I thought the idea was that there weren't enough two-person carpools using the HOV lanes, and that the toll-for-single-occupant-vehicle proposal was to get more people to use them, thus alleviating traffic on the main highway by some small amount. I mean, when I hear Carlos Lopez with TxDOT say things like "The premise is to try to get every bit of capacity out of the HOV lanes", that suggests to me that they're currently underutilized. These paragraphs aren't saying that at all - quite the reverse, in fact. The idea here is to alleviate congestion in the HOV lanes; the effect on the main highway is not taken into consideration.

This feels bass-ackwards to me. Why do we care about whether the HOV lane is moving smoothly as opposed to whether it plus the highway it's attached to is operating at peak efficiency? If a switch from two-passenger HOV lanes to three-passenger HOV plus single-occupancy for a toll makes the HOV lane go faster but the main freeway go slower, is that a good thing? I don't think so.

Basically, I say the focus should be on improving throughput on each corridor as a whole, not on any one piece of it, and especially not on one piece of it to the potential detriment of another. Is anyone talking about that?

Burris said so few HOV lanes across the country have been converted to HOT lanes that it is hard to generalize about the results. But there usually is opposition to overcome, he said.
"Minneapolis took about 12 years to get theirs running" because of a perception that they were "Lexus lanes" designed to favor the wealthy, he said.

"In Maryland, the governor said he didn't want to hear the words 'HOT lanes' anymore," Burris said. The main headache there, Burris said, was coordinating the toll rules on roads that passed through multiple states and the District of Columbia in a short distance.

So we don't really have any idea what effect this policy might have, though I think we can take a few good guesses. Is it so much to ask that in the event we do some kind of HOT pilot, we do a study to see if it makes things better, worse, or about the same for both the former HOV lane and the main highway? You know, like we're supposed to get for the accident rates at red light camera-enabled intersections, only maybe a bit more timely.

Burris said the easiest transition probably was in Houston when Metro began its QuickRide program on the Katy and Northwest freeways. The program allows two-occupant vehicles to use the HOV lane for a $2 fee during peak hours, when the three-plus requirement is in effect.

The move probably was accepted easily because "it wasn't seen as selling rides to single-occupant vehicles," he said.

This at least sounds like a reasonable place to start, though again it'd be nice to know what the effect is if you try it. What do you say, TxDOT and Metro?

Posted by Charles Kuffner on July 31, 2007 to Planes, Trains, and Automobiles