Police reopened the Nimitz Highway offramp in the Ewa direction of the H-1 Freeway following a motorcycle accident that left a 33-year-old man in “extremely critical” condition.

The motorcyclist crashed at about 6:05 a.m. near the Nimitz off-ramp, according to police and an Emergency Medical Services report.

Police said the man sideswipped a curb, lost control of his 1991 Honda motorcycle and skidded across the highway, hitting a concrete barrier on the other side of the road.

The man was wearing a helmet.

Police are still investigating whether speed or alcohol was involved.

Honolulu Police closed the offramp until about 9 a.m. while Traffic Division officers investigated the crash scene.