Boosting Drawbar Trailer Safety

boosting drawbar trailer safety

On the issue of boosting drawbar trailer safety, Bob Woodward, Australian Trucking Association Chief Engineer has campaigned long and hard to improve safety in this area.

For years there have been strong concerns from industry regarding the key technical safety aspects of drawbar trailers, especially the use of Susie coil airlines for the emergency brake function in a breakaway.

So… what’s a Susie coil? Susie (or Suzi, Suzy) coils originally referred to self-coiling suspended insulated electrical lines. The technology has since been adopted for airlines, called air Susie coils, although it’s advised that these types of connections should only be used in semi-trailer applications.

A breakaway occurs when a towed trailer accidentally disconnects from the towing vehicle and, if fitted, the safety chain also fails.

For drawbar trailers it’s important that when a breakaway occurs, the supply airline is disrupted and the emergency brakes function. That’s why it’s recommended that rubber hose instead of Susie coils is used, so that the emergency brakes actually work.

To combat this issue and provide best-practice advice, the ATA’s Industry Technical Council came together to develop a set of guidelines that provides operators with consistent and clear advice about the design, fabrication, and maintenance of drawbar trailers. The guide also covers the installation of towing eyes that are not in accordance with manufacturers’ recommendations.

To develop the guidelines, the ITC established an expert member working group made up of coupling suppliers, drawbar trailer operators and engineering consultants, who came together to outline processes for safe, optimum component performance.

Published as a Technical Advisory Procedure and available on the ATA website, the voluntary guide has been designed to meet the needs of industry and fill the gaps in vehicle standards.

The use of Susie coils is not a new issue, and it is vital the emergency brake system be designed to function and perform in accordance with Australian Design Rules.

Back in 2015 the ATA issued a safety alert about the use of Susie coils, and there have been known examples of drawbar trailer breakaway where the emergency brakes didn’t apply because of the type of airline connection.

That’s why we have taken practical action to improve safety for operators, drivers and everyone who shares the road. The guidelines address the issue by outlining best-practice procedures to improve personal and vehicle safety.

Developed by operators, for operators, implementation of these guidelines can deliver real safety benefits, while boosting drawbar trailer safety, for not only trucking businesses, but also prime contractors, major project consortiums, construction vehicles and the wider community who we share our roads with every day.

The ATA Industry Technical Council has an extensive library of Technical Advisory Procedures covering a range of relevant topics, including side underrun protection and heavy vehicle visibility, many of which have been adopted by project managers and operators across Australia.

boosting drawbar trailer safety