A 29-year-old Kapolei man died yesterday after crashing his motorcycle on the 'Ewa off-ramp of the H-1 Freeway, police said.

Honolulu Police Sgt. Danny Kaholokula said the 11:45 a.m. accident involved a 2005 Yamaha YZF-R1, which witnesses said was speeding past vehicles in the left lane on the off-ramp before veering off the roadway.

The driver was thrown from the motorcycle and landed against a steel directional signpost.

The Honolulu medical examiner's office identified the man as George Casher of 'Ewa Beach. He was pronounced dead at Queen's at 1:02 p.m.

It was not known whether the motorcyclist was wearing a helmet, police said.

The death is O'ahu's 30th traffic fatality of the year and fifth involving a motorcyclist. In 2007, motorcycles accounted for 15 of O'ahu's 68 traffic deaths.