An ambulance responds to the scene of an emergency.

A pedestrian suffered serious injuries after being hit by a car on an Interstate 70 ramp, the Wheat Ridge Police Department announced.

Police said the collision happened about 1 a.m. Thursday on the eastbound Highway 58 ramp to Interstate 70.

A witness told police the pedestrian was walking on the ramp when they fell over, possibly because of the wind from a passing semitruck. While on the ground, another passing vehicle struck the pedestrian.

The pedestrian was taken to a hospital with life-threatening injuries. Their condition is unknown, police said. The pedestrian’s family has been notified.

Police said the circumstances surrounding the collision are still unclear as of Thursday morning. No arrests or criminal charges have been announced in connection to the collision.

The investigation is ongoing. The Highway 58 ramp was closed for nearly six hours as police processed the scene.