An Associated Press analysis identified about 50 bridges that are "structurally deficient" and "fracture critical."
A bridge is "structurally deficient" when it is in need of rehabilitation or replacement because at least one major component is deemed in poor or worse. A bridge is deemed "fracture critical" when it doesn't have redundant protections and is at risk of collapse if a single, vital component fails.
The Skagit River bridge that collapsed in May was a fracture critical bridge, but it was actually not in disrepair like some of its peers.
While some of the bridges identified by the AP analysis are small spans in low-travel areas, others are prominent. They include an Interstate 5 bridge that carries northbound drivers over the east fork of the Lewis River, another I-5 span over the Stillaguamish River, and a Capitol Blvd bridge in Olympia that carries many government workers over Interstate 5 and into the city.
The span over the east fork of the Lewis River was built in 1936, and officials hope to replace it in the coming 10 to 15 years.
Because of age, corrosion and metal fatigue caused by vibration, the state has implemented weight restrictions on the bridge. Washington state Department of Transportation spokeswoman Heidi Sause said the bridge wasn't built for the kind of wear - bigger loads and more traffic - that is now common.
"This is a bridge that we pay close attention to and we monitor very carefully," Sause said.
AP's analysis looked at 607,380 bridges in the most recent federal National Bridge Inventory. It found that 65,605 bridges around the country were classified as "structurally deficient" and 20,808 as "fracture critical." Of those, 7,795 were both.