Westbound traffic on the Chesapeake Bay Bridge is recovering after a major crash Friday morning that prompted a medevac helicopter to land on the bridge.

In a news release, the Maryland Transportation Authority said the crash happened shortly after 11:30 a.m., when a passenger vehicle swerved from the eastbound lanes into a westbound lane, colliding with a tractor-trailer. MDTA said the reason the car went off-course is still not clear.

The medevac helicopter took the driver of the passenger vehicle to a nearby hospital to be treated for “serious injuries,” MDTA wrote. The driver of the tractor-trailer was not injured.

The crash shut down all westbound lanes of traffic for over an hour. All lanes were reopened by 2:30 p.m.

The MDTA is still investigating the crash, and asks anyone who witnessed the accident to call MDTA Police at 410-295-8146.