He said it was possible the driver fell asleep.
Mr Rapaea's death is the seventh on Hawke's Bay roads this year, and is the fourth road fatality in the Hastings District.
Police said it was not known how or why the car crashed and there were no other vehicles involved. The grey Ford Fairmont appeared to have rolled into a roadside ditch.
A St John Ambulance spokeswoman said when services arrived at the scene on SH2 between Waipukurau and Hastings the driver was missing.
She said they worked on the passenger of the car, Mr Rapaea, but were unable to revive him.
Police had used a drone to find anyone from the car in the nearby toetoe and maize bushes.
Mr Ubels said they had used the drone to make sure the driver had not crawled into the bushes and died.
The drone belonged to Tim Whittaker, Hawke's Bay's only certified drone pilot.
Mr Whittaker said with the dense toetoe and maize bush on either side of the road Police were unable to locate the driver on foot.
"They did a big ground search but they couldn't find him", he said, "I filmed the scene and covered the ground in about quarter of an hour."
The New Zealand Transport Agency said the crash happened about 3.50am near the intersection of Boundary Rd.
Police are keen to hear from anyone who may have seen the crash or noticed a grey Ford Fairmont driving erratically on the highway early this morning.
Police are also seeking sightings of anyone possibly on foot in the area who appears injured.
The New Zealand Transport Agency reported there had been one road fatality in Wairoa, one in Napier, and and one in Central Hawke's Bay. In 2015 the total road toll was 17, with 20 fatalities in 2014.
Less than a month ago Amberley Muller, 19, died on the same stretch of State Highway 2.
The Waipawa woman was travelling south along SH2 near Hastings when her vehicle crossed into the path of an oncoming truck.
The Nissan Cefiro she was driving become wedged under the truck, about 1km south of the Pekapeka wetlands.
Fire crews spent a number of hours cutting her body from the wreckage after the three-vehicle crash.
A 20-year-old Hastings woman involved in a motorcycle collision on SH50 on March 5 remains in a critical condition in Wellington Hospital's Intensive Care Unit.
