Reducing Traffic on I-405 in Los Angeles

An article in Saturday’s New York Times focused on the traffic problems being created by the three-year construction that’s adding a northbound carpool lane to the hugely congested I-405 freeway through the Sepulveda Pass. Adam Nagourney writes:

The intersection of Interstate 405 and Sunset Boulevard, cutting through a prosperous stretch of rolling Los Angeles hills and estates, is notorious for its knots of traffic and frustrating delays. Traffic is so bad that it is hard to figure out how it could get any worse. Well, a $1.3 billion highway reconstruction project that began with a blizzard of alarming detour signs the other day is about to make it much worse. And that has put a large part of this city on edge.The goal would appear simple and even admirable: to add a 10-mile car-pool lane on the 405, among the most reviled and traffic-snarled freeways in Los Angeles, as it approaches and rolls north over the Sepulveda Pass, connecting the city’s west side to the San Fernando Valley. But given the nature of this particular operation — basically open-heart surgery on the central circulatory system of this traffic-obsessed town — it is anything but.

I know that route well; I spent more than a decade commuting from the San Fernando Valley to the Reason Foundation headquarters in West LA, adjacent to the 405. The project is necessary, despite the short-term pain, but there are two big lessons this difficult project should teach us.

To get to the first lesson, we must ask why more capacity wasn’t added to this linear parking lot long ago. To be sure, a carpool lane was added in the southbound direction of the 405 about a decade ago. That project, too, faced opposition from those who said “we can’t build our way out of congestion” and from NIMBYs who objected to the construction itself. But besides these objections, which did delay the project, the underlying reason was that there simply wasn’t enough money in the Caltrans budget—given the other priorities set by elected officials—to build that expensive new lane.

Since then, construction has gotten more expensive in general, and because adding the current northbound lane requires widening bridges that pass over the 405, its cost is even higher. It’s only the addition of federal stimulus money that finally got this project over the cost hump and able to start construction.

And that leads us to lesson number one. We could have paid for a considerable portion of both the northbound and southbound lanes had they been conceived as express toll lanes rather than carpool lanes. It’s not as if Southern California didn’t know this option existed. Just 40 miles to the south of Sepulveda Pass, on SR 91, the nation’s first such express toll lanes have been in operation in Orange County since December 1995. By charging a variable toll that differs by time of day, based on traffic levels, the Express Lanes remain uncongested and operate at the speed limit even during the worst rush hours. And they are paying for themselves, based on the toll revenues.

To their credit, LA Metro and Caltrans are in the process of converting the carpool lanes on two freeways—the El Monte (I-10) in east LA and the Harbor (I-110) in south LA—to high-occupancy/toll lanes—a hybrid of carpool and express toll lanes. That’s a long-overdue good start. But the idea should have been used a decade ago to add express toll (or at least HOT) lanes to the 405 through the Sepulveda Pass.

Lesson number two stems from the huge disruption that will be caused by the three-year construction period. It will be that bad for one simple reason: there are no good alternative routes anywhere on the West Side between the LA Basin and the Valley. That’s a problem not only during the current construction on the 405. It was a massive problem during the Rodney King riots (when it took me over two hours to go the 10 miles to my house in the Valley). It’s a problem when a big-rig jackknifes on either the 405 or the 101 through Cahuenga Pass (the only other route). It’s a problem if there’s a brush-fire in either Pass. To say nothing of evacuating parts of the Basin in the event of an earthquake, a major riot, or a terrorist attack.

A good transportation system includes what engineers call “redundancy.” That means alternatives if your normal option is not available. It was the key insight that led to the Internet—sending packets of data through a well-connected network, so that if there is trouble on one part, the data can be routed around it. The original plan for the Los Angeles freeway system provided redundancy of that sort, with four or five routes between the Basin and the Valley. It’s too late—and far too costly—to bring back that plan. But we really do need more than just two routes between these two major portions of the city, and we need them sooner rather than later.