91 Freeway to close for 12 hours tonight

All lanes of the 91 Freeway -- the major east-west artery between Orange and Riverside counties -- will be shut down in Corona for nearly 12 hours beginning tonight, a closure that Caltrans officials warn could cause hours of delays for drivers who fail to use alternative routes.

The closure of the highway at Green River Road is scheduled to begin at 11 tonight and end at 11:30 a.m. Sunday.

California Department of Transportation officials said the route must be closed to allow workers to remove a bridge that is falling down, part of a two-year, $21-million project to replace it with a wider bridge. The work is scheduled to be completed later this year.

Because there are no easy bypasses through the canyon, Caltrans officials advise drivers to use the 10 Freeway, the 60 Freeway or California Highway 74, a route that has been closed for construction but will be reopened from 8:30 tonight until 4:30 a.m. Sunday.

The destruction of the old bridge comes after the completion of the eastbound lanes of the new bridge. Officials said, however, that those lanes need to be closed during demolition for safety reasons. The one exception will be for nearby residents who will be allowed to cross because they have no alternate outlets, said Caltrans spokeswoman Shelli Lombardo.

Others traveling in the area should plan to exit the 91 far in advance of the Green River Road bridge, particularly those driving west, she said. “Diversion is the key. Once they pass the 55 [Freeway] and they get down into the Santa Ana Canyon, delays can be extensive,” Lombardo said.

During a recent closure of the 91’s eastbound lanes at the construction side, hundreds of drivers who got off the freeway at the last minute were delayed for five hours, she said.

About 22,000 drivers use the Green River Road bridge each day, and Lombardo said Caltrans scheduled the demolition during nighttime hours, when studies show traffic is lightest.

Caltrans has advertised the weekend shutdown on permanent lighted signs along the 91, as well as in newspapers and radio ads.

In addition, officials contacted newspapers in Arizona and Nevada, which ran notices about the closure.

“A majority are California travelers, but we do know there are a portion of people from out of state, especially the Las Vegas run,” Lombardo said. “This way, they know in advance and can take an alternate route.”

For more information, call (800) 427-7623 or visit www.caltrans8.info.

molly.hennessy-fiske @latimes.com