California highway officials are hoping the closure of a 10-mi. stretch of one of the busiest freeways next weekend is a rerun of last year's two-day closure of the same segment of Interstate 405, but some fear apathy may cause a real traffic nightmare this time around.

Warnings of a potential traffic nightmare kept hundreds of thousands of motorists off the highway during the I-405 closure last year — dubbed “Carmageddon” — making it one of the lightest freeway traffic weekends ever.

Now “Carmageddon II” is upon us as CalTrans plans to again close a 10-mile stretch of the busy I-405 at the Sepulveda Pass over the last weekend in September. On Sept. 29 and 30 freeway will again be shut down between the 10 and 101 freeways for 53 hours.

Although officials are hopeful that motorists will again heed warnings to avoid highway travel during the closure, some believe the lack of problems during the first Carmageddon may cause apathy among motorists.

If thousands of people hadn't stayed home when the highway was closed last year, authorities say it could have caused a traffic backup so massive it could have spread to connecting freeways, gridlocking the entire city highway system.

"The risk factors are exactly the same as they were last year, so nothing has changed in terms of the heartburn that traffic agency people are feeling right now," said Dave Sotero, a spokesman for the transportation authority.

L.A. County Metropolitan Transportation Authority officials say the work project is more complicated this time around and highway users are warned to stay off local freeways over the Sept. 29-30 weekend whenever possible. Officials have been posting flashing freeway signs for weeks warning people all over the state to stay away.

"More motorists may now be tempted to rejoin local roads and freeways, which has the potential to create the very traffic congestion and multi-hour delays transportation and law enforcement officials have warned about," a Metro news release stated.

As with the previous I-405 closure, Sepulveda Boulevard is intended as an alternate route for local resident access only. Sepulveda Boulevard does not have the capacity to accommodate both local and diverted freeway traffic. Motorists should instead use alternate regional freeway routes to completely bypass the area. These include the 5, 15, 23, 55, 57, 101, 118, 126, 210, 605 and 710 freeways.

The freeway is scheduled to reopen by 5 a.m. October in time for rush hour traffic.