Smithfield, N.C. — The low height of some bridges over Interstate 95 in Johnston County has raised concern among truckers and transportation officials.

"Low bridges are a problem. They should have been raised years ago when they were building them," truck driver Kyle Johnson said.

Johnson said he's never hit the underside of an I-95 bridge, but he's seen several low-clearance crashes over the years, including one a few weeks ago.

"Any time you have an accident, you have a backup," he said.

Most drivers said truckers unfamiliar with the area are most likely to hit the low bridges. But they're also a hassle for veteran drivers who know where they are.

Trucks have hit at least three interstate bridges in Johnston County this year. State Department of Transportation engineers called that an unusually high number, but said it's tied to the age of the bridges – older bridges are often lower because they were erected to old construction standards.

A bridge near Four Oaks is one of the lowest in the area and has special sensors to warn over-height trucks. But DOT engineers said the warnings don't always work.

So, the DOT plans to raise four bridges over I-95 in Johnston County by 2 feet each next summer. Federal highway money will pay for the $4 million project.

Crews plan to raise one bridge at a time to minimize delays, and each one could take several days to complete.

"Right now, if you're oversized, you have to get off and go around and over the on ramp and come back out on the other side, so it would be a good idea," truck driver Martin Bowles said.