This post has been updated.

A pedestrian was struck and killed this morning on Interstate 270 in Germantown, prompting lane closures that jammed traffic in the area for most of the morning commute.

Investigators shut down the ramp at exit 15 (Route 118/Germantown Road), and one lane and one of the shoulders were also blocked.

The cause of the collision is unknown. Police said the striking vehicle remained at the scene, and the crash is under investigation.