Wednesday, January 06, 2010

I-405 Expansion in LA Offers a Case Study of the Fundamental Law of Traffic Congestion

Do new roads mitigate traffic congestion? You might think that extra supply allows a finite number of vehicles to move faster but transport economists haven't believed this. Duranton and Turner have done the best empirical work on this subject. Now, an expansion of the 405 Freeway in LA offers a specific case study. At the end of this piece , you will see some skepticism from two quoted reasonable people.

Economists reason that you shouldn't forget the extensive margin. If people sense that a highway now offers faster speeds this lowers the time price of driving on it and new people will come up with new trips on this now faster road. This increased demand will continue until the speeds slow down to the original sluggish pace.

Of course, what we need here is some road pricing with a time of day charge. Not everyone needs to be on the 405 from 730am-945am and 4pm-630pm. For example, UCLA faculty could reposition their teaching times to not be on the 405 at such peak times. A time of use varying charge would push these cheapskates off of the road and help everyone to save their most scarce asset (our time).

I-405 Sepulveda Pass Widening Project to begin Thursday
By Sean Greene
UCLA Bruin Newspaper

The 405 Freeway will undergo a three-year, $1 billion expansion project, beginning Tuesday, that will add a new carpool lane in the stretch between the 10 Freeway and the 101 Freeway.

The I-405 Sepulveda Pass Widening Project will create a 10-mile northbound lane to accommodate carpoolers, buses and other multiple-passenger vehicles. About 15 percent of the vehicles that travel the route daily contain multiple passengers, according to Los Angeles Metropolitan Transportation Authority spokesman Dave Sotero.

“The extra (high-occupancy vehicle) lane can absorb these vehicles, which will help improve and more evenly distribute traffic flows across all freeway lanes,” he said.

The northbound stretch of the Sepulveda Pass is the last stretch of highway to receive a carpool lane.

The project will also reconstruct the Sunset, Sepulveda and Skirball bridges and realign 27 on- and off- ramps. It is scheduled for completion in 2013.

Although the immediate impact of the construction project on UCLA’s commuters is not yet known, Sotero said there will be a “net benefit” for traffic flow in all lanes once the project is complete. Studies show that vehicles can save one minute per mile by using the carpool lane during peak commute periods.

To avoid congestion from construction, L.A. Metro suggests finding carpool partners and finding alternate routes in daily commutes.

Dan Raysh, a second-year business and economics student that commutes to campus, said last quarter traffic on the 405 often tripled his commute time, he said.

However, he said he thinks the expansion will not help congestion in the long run.

“An extra lane will cause more people to use the freeway,” Raysh said. “It’s a temporary change at best.”

Geography professor Antony Orme agreed that widening the freeway will not solve the problem either.

“It will be all right for a few years, but it will get clogged up again,” Orme said. “Eventually we’re just going to have renewed gridlock.”

Orme said the increased traffic on the freeway will come from new developments in the area. “They’re always trying to build the freeway for the decade passed,” he added.

Orme said the solution he’d like to see, although costly, is an increased push for mass transit in Los Angeles. He said there is no easy solution to the problem of congestion.

UPDATE: Internet Congestion offers another test of the "fundamental law". Internet Service Providers continue to expand their network of wires and infrastructure in order to guarantee that Internet users will not suffer download delays. This sound familiar? Households respond by wanting to download bigger and bigger files (movies rather than songs and email) and the congestion returns. Time of use pricing on the Internet? We will see.