Joe Cortright of City Observatory recently published an interesting post on HOT lanes (high-occupancy toll lanes) and cited a research paper by Austin Gross (University of Washington) and Daniel Brent (Louisiana State University). The paper looked at the behavioral response of drivers to dynamic HOT lane pricing.
They way HOT lanes work is simple: when traffic is light, the price dynamically decreases; when traffic is heavy, the price dynamically increases to ensure a minimum level of service. That is, the price increases until enough cars leave the lane and driving speeds increase to some minimum threshold. In this case, it’s 45 mph.
The key takeaway from the report is that “value of reliability” appears significantly more important to drivers than “value of time”. Put differently: it’s less about the time I’m wasting in traffic and more about the uncertainty of not knowing when I’m going to arrive at my destination.
It’s for this reason that HOT lanes are used more frequently in the morning (when you’re running late for that meeting) than in evening (when you’re just on your way home from work).
Gross and Brent estimate that the spread is about 7.5x. The typical driver values saving time at about $3 per hour and reliability improvements at about $23 per hour! This is fascinating because we tend to focus a lot on time. But arguably what people really want to buy is greater certainty.
I can tell you that it’s definitely one of the things that I love about walking to work, or for that matter cycling somewhere. I always know how long it’s going to take.
