A recent study of HOT lane usage in Minnesota along the I-394 and I-35 corridors by Michael Janson and David Levinson of the University of Minnesota [PDF] found that, counter-intuitively, rising toll costs actually attracted more commuters based on the assumption of "downstream congestion." But, writes Eric Jaffe, "the price of HOT lanes may not be a reliable signal of traffic levels at all."
"For all the money spent on tolls during the period studied by Janson and Levinson, drivers only saved between 1 and 3 minutes on the MnPASS HOT lanes, which run for about 12 miles on I-394 and 16 on I-35," he points out.
"The disconnect between toll-cost and time-saved is pretty extreme. While the Minnesota Department of Transportation expects people to place the value of saving an hour of time at $15, the drivers studied by Janson and Levinson paid the equivalent of $60 to $120 an hour. And this situation isn't unique to Minnesota: in metro Seattle, on the SR-167 HOT lanes, drivers are paying on the order of $22 to save an hour, even though they express a willingness to pay only $9."
"In other words, one reason HOT lane drivers might be willing to pay such high tolls is that they think they're saving more time in traffic than they actually are."