One man received fractures to his foot which required surgery while another had a dislocated shoulder. Other passengers were shaken but not physically injured.
Ihaka admitted to police at the scene he had fallen asleep at the wheel due to tiredness from working long hours the previous week and then driving for several hours.
A blood sample taken at the hospital and analysed by ESR found Ihaka's blood contained Class A drug methamphetamine and tetrahydrocannibol (THC), the active ingredient in cannabis.
Another analysis determined there was no alcohol in Ihaka's system.
Ihaka admitted he was in charge of the vehicle at the time of the crash, acknowledged two people were injured in the incident and accepted full responsibility for causing the accident due to fatigue.
However, at a defended hearing before Judge Ian Carter in the Whanganui District Court on July 1, 2021, Ihaka's lawyer Blair Piper challenged whether the blood sample taken was correctly obtained under the Land Transport Act.
The act requires the person (unless they are unconscious) to be advised the specimen was being taken for evidential purposes.
The nurse who took the sample, who was not the health practitioner or doctor in charge of the examination, had been given consent by Ihaka to take the sample but had failed to inform him it was for evidential purposes.
Judge Carter released his reserved decision on Monday and found there was no evidence the correct procedure was followed to obtain the blood sample.
The undisputed facts, Ihaka was the driver, he caused the crash after falling asleep and two people were injured, remained.
He was initially charged with driving causing injury while his blood contained evidence of the use of a controlled drug.
Judge Carter amended the two charges to one representative charge of careless driving causing injury and found Ihaka guilty.
The charge carries a maximum penalty of three months imprisonment, a $4500 fine and six months disqualification from driving.
Ihaka was fined $1000 and disqualified from driving for six months; however, Judge Carter backdated the disqualification start date to July 2021, so it had been effectively served.