The court was told that one of the girls asked the driver to slow down before the crash.
"Two young people died in circumstances which were totally avoidable," Crown prosecutor Greg Hollister-Jones said.
Seated beside Reihana was Morehu's oldest daughter who was holding Reihana's 2-year-old daughter on her lap belted in a lap-restraint.
The Crown alleges the accused engaged in a high-speed, reckless, alcohol-fuelled chase reaching speeds of more than 100km/h. The group was heading towards a family funeral plot to visit the girls' grandmother's grave when the crash occurred.
During his opening address Mr Hollister-Jones told the jury that what occurred that day was "alcohol-fuelled madness" as all three accused were driving under the influence, in unregistered and unsafe cars.
Mr Hollister-Jones said on the day of the crash Brett McCready, 39, was driving in the opposite direction along Welcome Bay Rd when he was confronted by "every driver's worst nightmare".
Reihana, having overtaken two vehicles on the wrong side of the road, lost control and slid sideways into Mr McCready's ute, which flipped over backwards and landed on its roof. Mr Hollister-Jones said Reihana was breath-tested after the crash and found to be driving with 157 milligrams of alcohol per litre of blood, almost twice the legal limit of 80mls, but neither Morehu nor Davey was tested.
All three accused have made a number of admissions in relation to the case, the jury was told. Reihana admitted he was driving while suspended, Davey was an unlicensed, disqualified driver and Morehu had admitted she was flouting the terms of her restricted driving licence. Reihana also admitted driving drunk and the other two had admitted being under the influence of alcohol, Mr Hollister-Jones said. They have all denied they were racing.
During the three-week trial 36 witnesses would be called, including a Tauranga police crash investigator, who Mr Hollister-Jones said, has estimated the car Reihana was driving reached speeds of 142 km/h.
Both Davey's lawyer, Paul Mabey QC, and Morehu's lawyer, Glenn Dixon, made brief opening statements.
Mr Mabey reminded the jury that Davey and Morehu were only charged as a party to Reihana's alleged offending.
The lawyers said the Crown's case centred around whether they could prove beyond reasonable doubt that there was a race and that Davey and Morehu had actively encouraged or assisted Reihana in his actions.
The trial continues today with the jury making a visit to the crash scene.