November 16, 2012
In this LA Times story I found the following potentially false hope:
Transportation officials and some experts say the 110 Freeway experiment is a long-overdue, winning improvement that should benefit all drivers. It will reduce travel times for those willing to pay, they predict, and relieve congestion on the remainder of the freeway as solo commuters shift out of those lanes.
There’s not much evidence the express lanes will substantially ease congestion. For a while, some solo drivers will divert into the tolled lanes, but probably not enough to have a big impact. And demand in the free lanes is a function of congestion, so demand will rise enough to mitigate any congestion relief. Lastly, when the solo drivers merge with regular traffic it creates a big bottleneck. I recently did a detector data project showing that the SR91 HOT lanes in Orange County have a huge bottleneck when the HOT lanes end, as the solo drivers change lanes.
The real advantage of express lanes is the time savings of people who use it and, to some degree, the option value that everyone else gains. But even in a culture as allegedly individualistic as America, express lanes have to be marketing in terms of their congestion savings to the whole group. I worry, though, that this marketing strategy will backfire when opponents start asking, “Where is the congestion relief you promised?” at the end of the trial. This is a sore point on the despised Atlanta HOT lanes.
The 495 Express Lanes are opening in DC on Novemeber 17th. This is a very big deal, because America’s bureaucrats and political tastemakers will finally have first-hand experience with the idea. Unfortunately, the 495 express lanes are compromised by a forced merge when they get to the beltway, which will substantially neutralize the savings for both their customers and the general traffic.