Martin Wachs  (above left), a distinguished professor emeritus of Urban Planning, and Urban Planning professor Brian Taylor , who directs the UCLA Lewis Center for Regional Policy Studies  and the UCLA Institute of Transportation Studies , have an op-ed in the Los Angeles Daily News  that examines lessons learned during "Carmageddon," the full closure of the 405 freeway for major construction during a weekend in July 2011.
The piece appears slightly less than two months before Carmageddon's sequel, which is slated to take place September 28-30.
Using an analysis of traffic patterns before and during Carmageddon, Wachs and Taylor conclude that when area residents were confronted with predictions of congested detours and increased travel times, most drivers elected to stay home. "Because there is no evidence that substantial numbers of travelers took detours around the closure, shifted to public transit, or shifted their usual travel to before or after the closure, the vast majority of people who would have traveled through the Sepulveda Pass must have chosen not to attempt the journey over the hill at all," they write.
How dramatic was the decline in travel? In areas nearest the closure, traffic levels were down by as much as 73 percent compared to a normal weekend. The effects of the closure were felt throughout Southern California's freeway network—"Statistically significant reductions in traffic flows occurred as far as 80 miles from the closure," Wachs and Taylor report. Transit ridership was also down between 9 and 30 percent on bus routes near the closure, they say. As the weekend continued and it was clear that movement around the area was possible, traffic levels began to tick back up.
Wachs and Taylor trace this change in behavior to the overwhelmingly ominous tone of public warnings made in advance of the closure. By "emphasizing the potentially dramatic consequences" of driving during the construction weekend, the authors say, public officials helped scare people away from their vehicles and prompted them to stay off the roads entirely during the shutdown.
This approach may not be as effective the second time around, though, since previous predictions of traffic doom failed to materialize. For Carmageddon II, Wachs and Taylor advise public officials to appeal to Southern Californians' "public spirit," asking residents to work together to make the sequel go as smoothly as the original.