Honolulu Police opened a traffic investigation after the condition of a bicyclist hit by a vehicle in Aiea was downgraded to critical.

Police said the man was initially taken to the hospital in serious condition following the accident on Pono Street near the Moanalua Road intersection at 11 p.m. Friday.

Police said the bicyclist was crossing Pono Street when he was struck by a vehicle driven by an Aiea man.

His condition worsened in the hospital.

The bicyclist was not wearing a helmet, police said.