Thanks to the speedy replacement of a collapsed 160-foot section of the Interstate 5 Skagit River bridge—seen in this video—traffic is once again flowing between Seattle and Vancouver, British Columbia.

A part of the bridge collapsed on May 23 when it was struck by a truck carrying an oversize load, causing a car and another truck to fall into the river. Three people had to be rescued.

Normally, the bridge carries 71,000 vehicles a day. The temporary span, which cost $18 million, is only a short-term fix. Construction of a permanent bridge replacement is set for this fall.

The structure is one of thousands in the U.S. considered “fracture critical,” meaning that if one critical part of the bridge is compromised, it could crumple.

A report from Transportation for America recently estimated that 11 percent of all bridges fits this description.

An AP report estimates that thousands of the “fracture critical” bridges were built in the U.S. from the 1950s through the 1970s—and are still in use. It also notes that making all the needed fixes would cost billions.