A report into a tuk-tuk crash in Wellington late last year has revealed safety testing flaws put passengers at risk, and probably led to the injuries suffered by six people on board.
The $30,000 investigation into the crash, on Wellington's steep and winding Roseneath Tce in December, was commissioned by the New Zealand Transport Agency after its inspection of the tuk-tuk following the incident raised concerns about its stability and "rollover" strength.
According to the report, obtained under the Official Information Act, five passengers suffered head and facial injuries in the accident, including concussion, cuts and bruises, which required emergency medical care or hospital treatment.
The report says the vehicle's metal canopy offered "little to no resistance" to the crash, and its supporting pillars also failed to withstand the impact.
Tuk-tuks were certified as passenger service vehicles in September, and operated in Wellington and Auckland until they were taken off the roads in February.
The report, signed off in January, shows the vehicles were incorrectly given safety certificates and, had the issues been addressed, "the level of injuries would likely have been reduced".
"The condition of the vehicle does not meet the expected behaviour of a rollover frame; the vehicle structure has failed to provide reasonable protection to occupants."
WHY WERE TUK-TUKS INCORRECTLY CERTIFIED?
NZTA hired Palmerston North-based company Sandbox Consulting to investigate the tuk-tuk's performance in the crash and, subsequently, to recommend design changes to improve the vehicles' stability.
According to the report, the error occurred because shortcuts were taken during safety testing that deemed the tuk-tuks to be roadworthy.
NZTA rules require a passenger service vehicle to be able to withstand an impact, at its highest corner, of half its maximum weight from side-on and total unladen weight from above, without sustaining permanent damage.
The independent engineer who issued the safety certificates for the vehicles operated in Wellington by Tuk Tuk Cartel erred by assuming the three-wheeled tuk-tuks would absorb the impact in the same way as heavy vehicles, such as buses, the report says.
The incorrect method was used for "expediency", when a separate analysis should have been carried out.
Unlike a heavy vehicle, the tuk-tuks would be unlikely to evenly distribute the force of any impact, making the front more vulnerable should it hit the ground and potentially "leading to failure".
The report also finds the steel canopy did not qualify as a rigid structure, as is assumed of heavy vehicles.
The police serious crash unit investigated the accident and deemed neither the driver nor Tuk Tuk Cartel was at fault.
Glen Varcoe, who set up Tuk Tuk Cartel with his brother Jeremy Marr, said the report appeared "interesting", and he would take a couple of days to consider it before commenting further.
NZTA said on Monday that the independent engineer involved was currently being investigated by the Institution of Professional Engineers.
He was issuing safety certificates as "a suitable qualified person", an NZTA spokeswoman said, but was not an NZTA appointee.
"Because there is an ongoing investigation, the Transport Agency is not able to comment on the circumstances that resulted in the vehicles being deemed compliant with PSV requirements.
"All Transport Agency-appointed independent vehicle certifiers are subject to performance monitoring and auditing by the agency with respect to certifications carried out under those appointments."
She added: "The process used for certifying the vehicles as passenger service vehicles was the correct one, but the crash investigation by the NZTA has indicated that the vehicles did not comply with the relevant technical requirements of the passenger service vehicle rule."
New testing criteria has been introduced to assess the stability of three-wheeled vehicles before they are issued with a certificate of fitness.
The testing will ensure "real-world stability" similar to that of a four-wheeled vehicle, and includes a raft of engineering calculations.
It was unclear whether the necessary improvements could be made to tuk-tuks to bring them to an acceptable safety level, the report said.
NZTA said it was up to tuk-tuk operators to decide if they wanted to reapply for an operating licence if and when they were deemed roadworthy.