About this Guideline

This guideline is intended to provide general information on trailer coupling, with the intent of eliminating or reducing miss-coupling incidents or what is commonly referred to as dropped trailers. Proper coupling of trailers is an essential skill for heavy vehicle drivers. Trailer coupling errors may have devastating consequences for other road users.

What risk factors contribute to dropped trailers 

Driver error is frequently found after independent expert examination of turntable and kingpin reveals no faults.

  • Often a driver new to their employer 
  • Often a temporary driver or newly hired subcontractor is involved 
  • Driver occasionally report being distracted or interrupted during coupling. 
  • Driver sometimes report being under pressure or recent criticism. 
  • B-Doubles require substantially more connecting and disconnecting if there are no B-Double unloading facilities. 
  • Rare instances of equipment failure  
  • Rare instances of vandalism of rig during rest breaks.

Dropped trailers cause significant damage to equipment and disruption at the point of incident. Some occur on public roads with considerable risks to other roads users.

What can Drivers do to prevent trailer coupling errors?

Know your company’s procedure and follow it fully every time. Don’t take shortcuts. This document is not a procedure, it is a guideline covering some key points, and different organisations will use their own procedures based on equipment combinations. This document is not intended to replace or over-ride your company procedure. However your procedure should include at least one tug test, but most important is a proper visual inspection of three essential points: 1. The turntable release handle must be in the engaged position. (Short not extended). If you get interrupted start over from the beginning. If you leave your rig unattended repeat coupling checks again, due to possibility of tampering with turntable release.

High-hitches (where trailer may travel many kilometres before falling away) are the most dangerous outcomes. They can be prevented by proper inspection of all three essential points detailed in this guide. Some turntables have an extra dog chain which can only reach the handle when it is fully retracted.