The accident took place in the vicinity of Morne Coco Rd and Diego martin Highway.
According to witnesses, around 10.45 am, David Fanan 58, of St Lucien Road, Diego Martin, was proceeding south along the highway on his motorcycle.
A car was exiting Morne Coco Road in an attempt to cross the highway and enter Diego Martin Main Road when Fanan crashed into the right side of the car.
The accident caused traffic to be backed up for close to two hours along both sides of the highway.
Officers said drivers were previously allowed to cross the highway from Morne Coco Road and enter the main road, but this was stopped with the opening of the new highway, as it had caused several accidents in the past.
Traffic signs were seen at the exit of Morne Coco Road warning drivers that entry was not allowed.
The driver of the grey Nissan Sunny that was involved in the accident was detained for questioning at the Four Roads station yesterday evening.
Investigations are continuing.