LEWISTON, Maine (AP) — A missing woman who was subject of a statewide alert was killed when her car was struck by a tractor-trailer early Wednesday on the Maine Turnpike, state trooper said.

Jean Robinson, 78, of Gorham, was stopped in a breakdown lane before pulling in front of the tractor-trailer, which hit her vehicle broadside shortly after 2:30 a.m. Wednesday in Lewiston, troopers said. She was pronounced dead at the scene. The truck driver was unhurt.

Robinson disappeared after she departed to visit a relative’s home in Southwest Harbor. A Silver Alert was issued Tuesday to law enforcement agencies to be on the lookout for her, officials said.

Similar to an Amber Alert for missing children, a Silver Alert triggers a search for people who are missing and who have dementia or other mental or developmental disabilities.