Updated at 7:00 p.m.

A police officer was seriously injured in a crash on Wednesday that closed down the Bay Bridge, then jammed traffic on U.S. 50 for 16 miles.

At around 6:40 p.m., more than six and a half hours after the accident, the Maryland Transportation Authority said that traffic in both directions had started moving smoothly again.

Around noon, the Maryland Transportation Authority officer who was injured in the crash was monitoring traffic from his vehicle parked in the crossover, the emergency-vehicles-only strip that connects the eastbound and westbound sides of U.S. 50, just east of the Bay Bridge on the Eastern Shore. A driver traveling on the highway veered out of his lane, crossed the median, and plowed into the police car, according to Maryland Transportation Authority Lieutenant Kevin Ayd.

Ayd said that the police car was pushed across all of the eastbound lanes, and the other car stopped in the leftmost westbound lane. Both the officer and the driver were flown in separate medevac helicopters to a shock trauma center at the University of Maryland, and both were in serious but stable condition on Wednesday evening, according to Ayd.

The crash, the landing of the two helicopters, and the investigation kept the road shut down after the collision. When it reopened, traffic backed up for 16 miles, from Exit 27 on the Western Shore to Exit 43 on the Eastern Shore.