Honolulu Police believe a moped driver may have fallen asleep before crashing along Kalanianaolw Highway.
The single-moped accident was reported just after 4:30 a.m. Friday near Kawaihae Street in Hawaii Kai.
According to the Honolulu Medical Emergency Services, a 25-year-old man was transported to the hospital in critical condition. Investigators say he was not wearing a helmet and alcohol does not appear to be a factor.
Police closed the townbound lanes of Kalanianaole Highway near Kuliouou Road while they investigated the scene.
All roads reopened just before 6:30 a.m.