A 39-year-old Waialua man began serving an 18-month prison term yesterday for killing a teenage bicyclist in a hit-and-run traffic collision in front of Dole Plantation more than two years ago.

A state judge sentenced Arnel Abuluyan to five years’ probation yesterday and ordered him to spend the first year and a half behind bars.

Abuluyan agreed to the probation when he pleaded no contest last December to leaving the scene of a fatal traffic accident.

He requested a postponement of the prison term. Circuit Judge Edwin Nacino denied the request and ordered him to prison immediately.

Nacino also ordered Abuluyan to perform 750 hours of community service and pay a $10,000 fine, and revoked his driving privileges for the five years he is on probation.

Police said Abuluyan, an installer for a carpet and flooring company, was driving a company van at about 1:30 a.m. July 22, 2008, when he struck 18-year-old David Wayne Aldridge Jr. from behind.

The state said Abuluyan was speeding and had been drinking.

Aldridge was riding home to Helemano Military Reservation from his job on Schofield Barracks at Burger King.

A tip lead police to Abuluyan and the van, which was at a Waipio body shop.

Abuluyan told police he thought he hit something but didn’t stop.

He has four speeding convictions, one each in 2002, 2006, 2008 and 2009. In October 2006 he drove 15 mph over the speed limit, in February 2008 he went 17 mph over the speed limit and in September 2009 he was 16 mph over the speed limit.