MOUNT VERNON — The Skagit River bridge on I-5 is slated to reopen Wednesday with slower speeds for vehicles and a ban on trucks hauling excessively large cargo like the one which caused it to crumble into the water.

A temporary four-lane span will open without fanfare just shy of a month after a semi-truck carrying an oversized load struck several of the bridge’s overhead trusses, causing a 160-foot section to fall into the river.

Two vehicles went into the water but the three people traveling in them survived the harrowing May 23 incident.

Gov. Jay Inslee visited the site Tuesday as workers paved and prepared to stripe the roadway, a major artery for commuters and commerce that carries an average of 71,000 vehicles a day.

There will be some new rules when the bridge reopens.

The maximum speed will be 40 miles per hour, down from the 60 mph limit in effect before the collapse. That’s because each of the four temporary lanes will be 11 feet wide, which is about a foot narrower than those on the section that fell into the water.

Nearly all cars, commercial vehicles and big rigs carrying legal loads allowed on the bridge before will be able to use it again, transportation officials said.

There will be a barrier between north and south traffic, but it will be made of steel trusses instead of the concrete that separates traffic on the rest of the bridge.

What won’t be allowed are trucks that require a special permit to travel on state highways because they exceed legal rules for height, width, weight or length, said Travis Phelps, a Washington Department of Transportation spokesman.

“If you’re getting a permit to drive on the highway, you won’t be going over this bridge. You’ll be using the detour routes,” he said.

Time-lapse video by WSDOT.

All traffic has been detoured since May 23 when the truck struck the 58-year-old span.

The Washington State Patrol and National Transportation Safety Board are conducting investigations in the cause of the collapse.

Atkinson Construction of Renton received a $10 million contract to demolish the damaged portion, remove debris from the water and put in the temporary four-lane segment that Acrow Bridge of New Jersey built.

On Tuesday, the state awarded a $6.9 million contract to Max J. Kuney Co. of Spokane to construct the permanent replacement span.

Under the contract, work must be done by Oct. 1. It will require closing the bridge for up to two weeks in September to put the span in place, but the closure cannot occur until after Labor Day, according to contract documents.

When the bridge is restored to its pre-collapse capacity this fall, it will still be rated as “functionally obsolete” because it was not designed to handle today’s traffic volume and big trucks. It’s also considered “fracture critical,” meaning that if a single, vital component is compromised, the bridge can crumple again.

Federal funds will cover 100 percent of the costs of the temporary fix and 90 percent of the permanent replacement.

Thus far the federal Department of Transportation has committed $16.6 million for the two projects from its Emergency Relief Fund. The federal agency provided $1 million in the days following the collapse and then last week pledged another $15.6 million.

With the announcement of the scheduled bridge reopening, Amtrak plans to cancel the extra round-trip train it added between Seattle and Bellingham following the span’s May 23 collapse.

Two round-trip Amtrak Cascades trains per day still run between Seattle and Vancouver, B.C. Amtrak also operates five round-trip Thruway Motorcoach buses between the two destinations.

Reporter Bill Sheets contributed to this story.

Jerry Cornfield: 360-352-8623; jcornfield@heraldnet.com