A truck driver reported that he was distracted just before he ran into the car in front of him, pushing it off of the Chesapeake Bay Bridge into the water 27 feet below.

The car’s driver managed to get out of the sinking vehicle and swim to safety with minor injuries.

In a preliminary report on the July 19 accident, the National Transportation Safety Board found that the momentary distraction was key to the collision.

The truck driver said he looked to his driver-side mirror because there were sounds and lights behind him, and when he looked forward again the cars ahead of him had stopped and he could not avoid the collision.

His truck pushed the car and its driver, a 24-year-old woman, up onto the bridge barrier. The crash broke a window, through which the woman escaped after the car hit the water. She swam to a bridge piling and waited there until she was rescued.

The incident attracted attention in the Washington, D.C.-Baltimore area, in part because the bridge can be an intimidating passage for some motorists.

At 4.3 miles, the bridge is one of the longest over-water spans in the world. It rises 186 feet above the Bay’s main shipping channel to accommodate ocean-going traffic to and from the Port of Baltimore. And it carries heavy traffic volumes, connecting the western side of the Bay to shore points in Delaware, Maryland and Virginia.

Some motorists find these features so daunting that they’ll pay $25 to have someone drive them across.

The truck was based in Canada, owned by Bulk Carriers PEI Limited. Its driver was on his first solo run without a more experienced driver, NTSB reported. He was a recent émigré from Hungary to Canada under a Canadian temporary foreign worker permit.

According to the Maryland Transportation Authority, the crash rate on the bridge is significantly lower than on other state roadways. Between 2008 and 2011, the bridge averaged 43 crashes per 100 million miles traveled, compared to 166 crashes per 100 million VMT statewide.