One bicyclist was killed and another critically injured today in separate collisions in Wahiawa and 'Ewa.

An 18-year-old Wahiawa man died at The Queen's Medical Center after being struck by a truck, possibly a red flat-bed, in a hit-and-run accident on Kamehameha Highway, six-tenths mile north of Nui Avenue near the Dole Plantation pavilion, said police vehicular homicide inestigator Sgt. John Agno.

The second victim, a 41-year-old 'Ewa man, suffered critical injuries after being struck by a 1992 Ford Aerostar van on Fort Weaver Road, 192 feet south of Keanui Drive,Agno said.

Today's fatality is O'ahu's 29th in 2008, second in as many days and fifth this month, and the 16th in a 69-day period since May 15.

It is also the second involving an 18-year-old in as many days. Natasha M. Taualai was killed yesterday on the H-1 after exiting a moving vehicle.

Today's fatal hit-and-run is the second since June 4 when Bonifacio Libosado Sr., 79, was struck by a light-colored van while crossing Dillingham Boulevard near Ka'a'ahi Street in Kalihi. Police have made no arrests in that case.

In today's case, the truck driver left the scene at 64-1550 Kamehameha Hwy. at 1:43 a.m. The truck should have extensive front-end damage, police said.

Anyone with information on the truck can call police traffic investigators at 529-3499.

The victim's identity hasn't been released yet. The victim was taken to Wahiawa General Hospital and then to Queen's by Emergency Services, Agno said.

The bicyclist was riding on the paved shoulder of the roadway, headed north on a single-speed Mongoose, when hit by the truck, Agno said. Speed may be a factor, he added.

Northbound traffic at the Joseph P. Leong bypass, Kamehameha Highway and Kamananui Road was diverted onto Kaukonahua Road while traffic investigators were at the scene.

In a separate accident on Fort Weaver Road at about 4:30 a.m., the bicyclist was struck by the van while attempting to cross the roadway from the right shoulder, said Agno.

The injured man suffered head and facial injuries and was taken to Queen's where his condition was unchanged this afternoon, police said.

The van's driver, a 40-year-old 'Ewa woman, was not injured.

Fort Weaver Road in the area of the accident was closed to north-bound traffic for about 2 1/2 hours. The roadway was reopened at 7:03 a.m,