RAND's Traffic Expert Replies to TTLA Reader

From TTLA reader JK: "In my commuting days to ucla I formed the opinion that there is a definite incompatibility with manual and automatic transmission vehicles with regards to constant traffic flow. At a incline metered on-ramp, the mt vehicles would prefer to be slow and steady leaving the vehicle in 1st gear with minimal gas applied. the at vehicles would like to jam fast then sit braked. The same occurs in slowed traffic (so called stop and go). driving a mt car, I found it preferable to settle behind a big rig (mt) and benefit from his smoothing of traffic. We should explore utilizing the "amber alert" sign to "suggest"(feedback) the slow and steady traffic speed (ie: around hughes center, near the 10 interchange etc). or even explore dedicated lanes as an extreme. is there any research as to the improved throughput benefits to curtailing driver stop and go impulses?"

From RAND's Paul Sorensen: "In our recent study of short-term measures for reducing traffic congestion in Los Angeles, we did not examine nor encounter research addressing the potential throughput benefit that might result from efforts to tame stop-and-go driver impulses, though it's certainly possible that researchers have looked at this question. What we can say is that stop-and-go traffic patterns significantly reduce freeway throughput capacity, and the propensity of some drivers to rapidly accelerate and decelerate can exacerbate the stop-and-go phenomenon."

Thanks to Sorensen, JK, and to UCLA's Donald Shoup as well.

Illustration copyright and courtesy Rich Nielsen 2009.