Stuck in Traffic — Will More Lanes Help?

It was once the top priority of the Santa Cruz County Regional Transportation Commisison (RTC) to widen Highway 1 in an attempt to relieve traffic congestion. Then the RTC came to the conclusion that the $600 million highway widening project is not financially feasible. So the RTC has scaled back the widening plan, proposing to spend $100 million to build auxiliary lanes from Santa Cruz to State Park Dr. The funds would be generated as part of a sales tax measure to be placed on the November ballot.

A relevant question is whether this smaller effort would have any measurable impact on traffic congestion. A Caltrans Draft EIR published in November, 2015, predicts that there would be "very slight improvement in traffic congestion" as a result of building what is called the TSM Alternative. The sales tax would fund a portion of the TSM Alternative.

And even minimal congestion relief is questionable, because Caltrans did not factor in the effect of "induced travel". A 2014 performance review of Caltrans by the Smart Transportation Initiative at the University of Wisconsin notes, "Caltrans has not come to grips with the reality of induced traffic and the relationships between transportation and land use."

Susan Handy, Ph.D., has studied induced travel for the California Air Resources Board. Handy writes, "Traffic congestion has traditionally been addressed by adding additional roadway capacity... Numerous studies have examined the effectiveness of this approach and consistently show that adding capacity to roadways fails to alleviate congestion for long because it actually increases vehicle miles traveled (VMT)."

Handy will explain why vehicle miles traveled increases when highway capacity increases and what communities are doing to deal with their traffic congestion.