Waka Kotahi New Zealand Transport Agency has issued a safety alert for owners and drivers of vehicles fitted with cardan shaft park brakes.

The safety alert aims to raise awareness of the limitations of the brake mechanism, including the potential risks of parking on slopes, the agency said.

Cardan shaft park brakes (also known as driveshaft park brakes) are fitted to many small to medium trucks and a small number of passenger service vehicles.

They differ from ‘normal’ parking brake systems by preventing the vehicle’s driveshaft from turning, rather than directly preventing the rear wheels turning.

Waka Kotahi has been working with industry since last year to raise awareness of the importance of safe use and maintenance of vehicles fitted with cardan shaft brakes.

Four incidents involving cardan shaft brakes in New Zealand have resulted in fatalities over the past decade, including brakes fitted to road vehicles as well as off-road equipment.

A previous technical bulletin issued by WorkSafe in 2018 provided information for vehicle operators on safe use of these brake systems and how they can fail. The Waka Kotahi safety alert provides further detail to advise owners and operators on how the brakes are designed, and what precautions to take when using them.

“Owners and drivers of vehicles with cardan shaft park brakes need to understand the brake’s designs, and their limitations,” said acting director of land transport, Neil Cook.

“A cardan shaft park brake is designed to hold a vehicle stationary, but it must be used correctly and in accordance with the manufacturer’s instructions.”

The design of the brake means the vehicle may roll away when parked on a slope, especially if the load is changing or if the vehicle is parked on an unstable surface.

Cook said drivers should avoid parking on slopes or use wheel chocks when parked on a slope and when the vehicle is jacked.

“In addition, drivers should be aware that the park brake lever may require more force than they are used to, especially if they don’t drive a vehicle with this type of park brake regularly. More force may also be required when the vehicle is fully laden.”

Vehicle owners are responsible for ensuring the brakes are serviced regularly to maintain performance.

“Keeping to the maintenance schedule recommended by the manufacturer is vital to ensure that these brakes perform properly,” said Cook.

“Owners also need to make sure that any person driving their vehicle knows it is fitted with a cardan shaft park brake and what the limitations of the brakes are.”

A more rigorous in-service check of the brakes’ performance using a Roller Brake Machine test during six-monthly Certificate of Fitness (CoF) inspections is expected to be introduced for most classes of vehicles cardan shaft park brakes from 1 October 2022.