An 18-year-old woman leaped from the Baltimore Drive overpass of Interstate 8 about 8:35 p.m. Wednesday, hitting the westbound lanes with a sound heard by witnesses in a parking lot overlooking the scene.

La Mesa police and Heartland Fire & Rescue were on the scene for more than an hour, blocking I-8 traffic in both directions for a time and later opening eastbound lanes.

A La Mesa officer tried to prevent her from jumping, but wasn’t able to halt the act, witnesses and police said.