A 21-year-old moped rider was critically injured in East Oahu after he rear-ended a stopped vehicle near the Halona Blowhole Lookout Sunday afternoon, police said.

The rider operating a Roughhouse moped was traveling westbound on Kalanianaole Highway when he rear-ended a stopped 2019 Ford Explorer shortly after 4:20 p.m., according to police.

The moped was observed passing other vehicles just before the crash.

Police said the rider was taken in critical condition to a hospital. He was not wearing a helmet at the time of the crash.

The Ford driver, 31, and his passengers, a 10-year-old girl and a 6-year-old boy, were not injured.

Police said speed was a possible factor in the crash.

An investigation is ongoing.