It’s a go.

Transportation officials are going forward with a plan to close the notoriously gridlocked 91 in Corona for an entire weekend in February.

The freeway carries 280,000 vehicles a day and serves as a crucial link between Inland Southern California communities and coastal jobs. It is undergoing a massive $1.4 billion makeover to add toll lanes, all-purpose lanes and sweeping connecting ramps.

Officials say as part of that they must erect a wood-and-steel structure to pave the way for a new Maple Street bridge over a wider freeway footprint. That temporary structure can’t be set in place while people drive below because of the risk to their safety, officials say. So they intend to close all lanes, on both sides, for 55 consecutive hours in a Carmageddon-like scenario.

John Standiford, deputy executive director for the Riverside County Transportation Commission, said Wednesday the closure will stretch 6 miles from I-15 to the 71, and extend from 9 p.m. Friday Feb. 19 until 4 a.m. Monday, Feb. 22.

The goal is to work around the dominant commute periods, Standiford said, and to do the closure early in the year to avoid the busy beach season that fills 91 lanes with huge numbers of cars on spring and summer weekends.

The commission, which finances and builds major transportation projects in western Riverside County, has been laying the groundwork for the monumental closure in recent days and meeting with Corona-area residents who sit on a 17-member advisory task force to discuss details. According to surveys and social media, there appears to be substantial support for the plan.

“Any alternative would be far worse,” said longtime Corona resident Don Fuller.

After consulting Caltrans, the California Highway Patrol, Corona public safety agencies, neighboring cities, the Orange County Transportation Authority and multiple area officials, Standiford said RCTC administrators decided Wednesday to move forward with the plan.

“We needed to make sure not only that it is doable, but that we have the support and cooperation of all the agencies that depend on the freeway,” he said.

And cooperation is expected to come from many directions. Standiford said, for example, the Transportation Corridor Agencies, which operates Orange County’s toll roads, has offered to post notices about the closure on electronic changeable-message signs.

Standiford added that RCTC is trying to ease distress of Corona-area residents who depend on the 91 to get to work Saturdays or Sundays. RCTC is in talks with Metrolink about possibly providing extra commuter trains to run that weekend.

Mostly, officials want to ease the pain of Corona residents by urging virtually everyone outside the city to stay out during the 55 hours — like they avoided west Los Angeles during the Carmageddon closure of I-405 in the summers of 2011 and 2012.

The commission intends to blitz the region with a “steer clear of the 91” message.

“We don’t want to have people driving through Corona to get to where they are going,” Standiford said. “The Corona community has been impacted in a significant way (already by the construction project).”

For decades, Inland commuters have meandered through Corona on streets such as Ontario Avenue and Green River Road to avoid the 91. That probably won’t be an effective strategy the weekend of Feb. 19-22, Standiford said.

“It would be very time-consuming to zip through the city,” he said.

Earlier this week, there was talk about of opening a lane or two for Corona residents wanting to get on, for example, west of Maple Street and head west away from the construction activity. But, Standiford said, “I don’t think there is going to be any local access.”

He said officials have decided to go with a complete 6-mile closure, in part because that will make it easier to divert motorists around the construction zone. Detours will direct motorists north to the 60 freeway —- via the 71 if coming from the west, and via the 15 if arriving from points east. The detour will be approximately 20 miles long.

Motorists near the closure area should allow for extra time. Officials anticipate delays of as much as four hours for drivers on I-15 or the 71 near the closure area.

During the closure, work also is planned on eastbound 91 near the 15.

The entire-weekend closure reflects an expanding statewide trend toward scheduling occasional lengthy highway shutdowns that are geared toward rapidly solving a construction issue with a lot of pain all at once, as opposed to a little at a time over many weeks, if not months.

Brian Taylor, professor of urban planning and director of UCLA’s Institute of Transportation Studies, said this week there will be more such closures in the future after the booming success of Carmageddon.

“The word was broadcast far and wide,” Caltrans spokeswoman Lauren Wonder in Los Angeles said of that campaign to get people to avoid the 405. “People heeded it and stayed away. They stayed home. They took advantage of public transit.”

Southern California motorists will get a chance to practice for the Corona 91 closure in a real-life exercise Super Bowl weekend. Caltrans and city of Los Angeles officials are preparing once again for a draconian shutdown in the nation’s second-largest city.

They plan to close 2.5 miles of the busy 101 freeway through downtown Los Angeles for 40 straight hours —- from 10 p.m. Feb. 5 until 2 p.m. Feb. 7. That closure is aimed at taking down the iconic but deteriorating, 84-year-old Sixth Street Bridge over the 101.

“Caltrans across the state is using this more frequently,” Wonder said.

There could be a sequel to what one task force member has dubbed Coronageddon. Officials say there may be a need for another full closure this summer to remove the temporary support structure for the new bridge.

Contact the writer: 951-368-9699 or ddowney@pe.com