Interstate 5 between Los Angeles and the San Joaquin Valley has been shut down repeatedly over the years by snow, ice, brush fires and serious accidents.
Usually the road is reopened within a few hours. But not this time.
Friday night's fiery tunnel crash is expected to leave the critical route between Northern and Southern California closed until at least Tuesday, Caltrans officials said. Only two massive temblors, the Sylmar and Northridge earthquakes, have halted traffic on the route for a longer time.
"This is a highly unusual event for such a critical area," said Douglas Failing, the Caltrans director for Los Angeles and Ventura counties.
I-5 is the primary north-south route for trucks ferrying goods to and from Mexico, Canada and the West Coast's six primary seaports, the largest being Los Angeles-Long Beach. It is a main artery for transporting produce from California's Central Valley and wood from Pacific Northwest forests. It moves commuters from fast-growing suburbs in the Santa Clarita and Antelope valleys to work in the Los Angeles Basin.
Hasan Ikhrata, planning director for the Southern California Assn. of Governments, said the economic impact of the closure is likely to be huge.
"The goods moving on the freeway are significant," he said. "The hours of delay [for drivers] will be in the millions."
Every day, motorists make nearly 225,000 trips along the stretch of road where the I-5 intersects the 14 Freeway. The figure includes some 20,000 trips by commercial trucks.
Because of all the freeway connections, the I-5 through the area can back up as big trucks and cars compete for space. The truck bypass lanes where Friday's accident occurred are intended to separate the slower-moving trucks from cars heading up or down the Newhall grade.
But even with the truck diversion, traffic along the vital stretch of pavement is getting so heavy that Caltrans officials fear it could become the region's worst bottleneck in the next 20 years, particularly if several large residential development projects now being planned are built.
Up to now, nature has been the freeway's biggest enemy.
Twice in the last 36 years, major earthquakes have brought down I-5 overpasses in the same general area as Friday's accident. The Northridge quake in January 1994 caused two 80-foot-high bridges at Gavin Canyon to collapse, about two miles from the 14 Freeway. It took four months to reopen the freeway that time.
And the Sylmar quake in February 1971 brought down connector ramps and buckled the interchange of I-5 and the 14 Freeway, an event that caused Caltrans to embark on a massive earthquake-retrofitting program on the state's freeways.
In January 2005, snow and ice from a severe Pacific storm closed a 40-mile stretch of Interstate 5, including Tejon Pass, for two days. Castaic, a small town at the southern end of the Grapevine, became a temporary home for hundreds of stranded truckers.
When delays occur, truckers pass the time watching movies in their cabs, listening to music, talking on their CB radios or sleeping -- if they are fortunate enough to have a rig with a bunk.
"Being in a solitary job, we get used to spending time alone and entertaining ourselves," said Johnny Harris of Los Angeles, who has been a trucker for 26 years. "You just have to ride it through when the freeway shuts down. Sometimes you have no option but to sit there."
The closure underscores the vulnerability of the region's highway network. The only other major north-south routes out of the Los Angeles area are U.S. 101 to the west or a combination of Interstate 15 and U.S. 395 far to the east.
Neither is a good alternative, Ikhrata said.
"The 395 is one of the most unsafe highways in the state and the 101 takes far longer to travel north," he said. "This is a lesson for planners. You can't put all of your eggs in one basket."