NZ Transport Agency Waka Kotahi (NZTA) has issued a safety alert following an incident where a logging truck’s trailer separated from the truck and continued along the road, crashing, and spilling its load across the road. Other vehicles subsequently collided with the logs causing damage. Fortunately, no major injuries were sustained by any occupants of the vehicles involved, however the incident has highlighted a major risk that must be addressed.

The safety alert provides critical advice to all heavy vehicle operators, heavy vehicle specialist certifiers and heavy vehicle service providers about the safe installation and operation of automatic de-coupling devices.

Any affected vehicles must be removed from service until key actions described in the safety alert are completed.

Safety alert: Risk of vehicle separation – air operated auto coupling devices  [PDF, 295 KB]

The key points of the alert are:

• Air operated automatic tow coupling devices must either be installed:
  1. according to the manufacturer’s instructions including all safeguards; or
  2. with a safety mechanism that ensures that unintentional trailer disconnection is not possible while the vehicle is moving.
• Where the air supply to operate an automatic tow coupling device is drawn from the brake system supply, protection of the brake system supply must be fitted and be certified by a heavy vehicle specialist brake certifier (HVEK category).
• Signage, instructions, and training should be provided to alert the operator of the device and ensure its correct operation.