A motorcyclist died in a single-vehicle collision on Kamehameha Highway in the Punaluu area late Sunday night, Honolulu police said today.

The motorcyclist, a man in his 50s, sustained critical injuries and was found dead at the scene, according to Honolulu Emergency Medical Services.

Police said that, at about 11:20 p.m., the man had been traveling northbound on Kamehameha Highway at a high rate of speed when he lost control of his motorcycle, was ejected onto the road and hit a rock wall.

He was not wearing a helmet.

Although speed appears to be a contributing factor in the crash, it is unknown if drugs or alcohol are also factors, police said.

It was Oahu’s 12th traffic fatality of 2023 compared with 14 at the same time last year.

The investigation is ongoing.