William Massey is a safety specialist with the Michigan Center for Truck Safety. He told the Grand Rapids Press that truck drivers not measuring load heights may be leading to the collisions with the 100th Street bridge over U.S. 131 in Byron Township, which has a 14-foot clearance.
"Ignorance of the regulations is a common occurrence," Massey said.
Two tractor-trailers carrying shipping containers hit the bridge in January, damaging beams. Both drivers were cited for carrying containers over the state's legal load height limit of 13 feet, 6 inches, if without a permit.
Bumps or undulations in the road may also be causing trucks to bounce higher and strike the bridge, Massey said.
Lt. Brad Cushman of the state police commercial vehicle enforcement division indicated that more inexperienced truck drivers may be on the road.
"We do see younger, maybe more inexperienced drivers in the trucking industry," Cushman said. "I don't know if that plays a part in it, but I just know the bridge hasn't changed."
Between 1985 and 2003 there were only six documented times in which the bridge was struck by vehicles with high loads. Michigan Department of Transportation officials said earlier this month that they believe the overpass has been struck up to 11 times in 2018, while police data and media reports show at least eight bridge strikes.
The department's spokesman John Richard said the number is startling when considering bridge strikes on all Michigan highways total about 30 this year. About 60 other bridges statewide have the same 14-foot clearance as the 100th Street bridge or less.
"That makes about one-third of them at 100th Street, so that is pretty unusual," he said.
State transportation officials plan to spend up to $15 million in 2020 to replace and upgrade the overpass.