Free Seminar. "Do HOV lanes Really Create Freeway Congestion?"

Before we leave the country for three weeks I wanted to mention a free seminar on HOV lanes and provide a bit of trivia on hybrid vehicles that was sent to me by UC Berkeley.

“According to the DMV, 50,679 hybrid decals were issued by the third week of March 2006.”

There were 1,924,483 registered autos in OC (as of Dec 31,2004). Of that total 5,216 had hybrid decals representing 10 percent of the total decals issued statewide. That HOV report shows that we have roughly 2.7 hybrids per 1000 registered autos.

As to the decals. LA county is first with 16,769 or 33 percent.

April 20: “Do HOV Lanes Really Create Freeway Congestion?”

Presented by Michael Cassidy and Carlos Daganzo, Professors, Civil and Environmental Engineering, UC Berkeley

Are underutilized HOV lanes bad? To answer this question, we describe methodologies for sorting out the causes of congestion and apply these methodologies to five Bay Area freeway sites, each with an underutilized HOV lane. We find that these underutilized lanes do less damage than we had originally expected. Observations of a merge bottleneck at one of the sites showed that the low flows in the HOV lane were compensated by smoother (higher) discharge flows in the regular-use lanes. Though this observation surprised us, it was predicted by a theory. That theory further predicted that bottleneck flows can be increased by introducing an HOV lane.

Our empirical results are at odds with an earlier study that attributed the congestion on our five Bay Area sites to the HOV lanes. Though our present results are more favorable, they do not say that all HOV lanes are beneficial; (far from it). For this reason, the seminar will also show how HOV lanes should be systematically monitored and evaluated to avoid possible disbenefits.

See also “HOV Lanes Work Better Than Motorists Think” in Spring 2007 NewsBITS

Open to the public and free.

Sponsors include the Transportation Graduate Students’ Organizing Committee (TRANSOC), the Institute of Transportation Studies, the University of California Transportation Center and the Department of Civil and Environmental Engineering, University of California at Berkeley and CH2M Hill.

Friday from 4 to 5 p.m. in 240 Bechtel on the UC Berkeley Campus, preceded by Cookie “Hour,” 3:30 p.m. in the Harmer E. David Transportation Library, 4th Floor, McLaughlin Hall.

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