A broken expansion joint cover on southbound I-5 in Seattle damaged multiple vehicles and left a huge traffic backup during the Thursday morning commute.
Three lanes of southbound I-5 were closed near S. Holgate S. while Washington State Department of Transportation crews worked on a repair. WSDOT originally thought it would be a quick fix, but the repair took over five hours.
At one point, the backup extended 10 miles from S. Holgate St. to Northgate. Drivers were advised to use alternate routes, but most other southbound routes were also clogged.
KIRO Radio traffic Reporter Shane Cobane said the traffic on all the southbound routes was the worst he's ever seen.
WSDOT said the joint causing the trouble is an old expansion joint, not one of those they've recently replaced in the area.
"Anytime that you have something that is 50 years old that sees this much traffic go over it, there's a possibility that they're going to fail," said WSDOT spokesperson Mike Allende.
WSDOT said it was the metal cover of the expansion joint, not the joint itself that broke in this case.
The Washington State Patrol reports at least three tow trucks had to be called to remove vehicles damaged when the metal cover buckled. There were more cars with flat tires.
Allende said the department has been working for the past year to replace a number of aging expansion joints on I-5. They've already had several weekend lane closures for the project.
Expansion joints help maintain a smooth driving surface by allowing the highway to expand and contract with changing weather.
The next weekend closure for expansion joint replacement work will be June 6-8.