A lot of emphasis is given to heavy vehicle GVM (Gross Vehicle Mass) and GCM (Gross Combination Mass) weights. These limits are set by regulatory authorities and vehicle manufacturers to minimise road damage and maintain vehicle stability while ensuring the vehicle is being operated within its engineering parameters.
GVM and GCM weights are quite easily manageable and recordable within freight operating software to ensure that loads scheduled for particular vehicles are within that vehicle operating weight range.
Where things can get a little more complex, particularly for fleet operations that do not have access to their own on-site weighbridge, is weight distribution. Trucks and combinations can be wholly within legal loading limits but if the load is not evenly distributed across the vehicle, serious safety issues can arise.
Who’s responsible?
In years gone by, the poor old driver was basically held responsible for pretty much everything related to the load, thankfully, much has changed.
With the adoption of HVNL (Heavy Vehicle National Law) and COR (Chain of Responsibility) legislation, responsibility for load management is shared by all involved in the transport chain, (including management).
The regulations
The regulations under HVNL with regard to weight distribution are quite non-specific when it comes to actual weights and what you can and can’t do with heavy vehicles and combinations, but the required outcomes are as follows.
Understand the HVNL and your primary duty
Under the HVNL section 26C, each party in the CoR has a primary duty to ensure the safety of its transport activities, so far as is reasonably practicable. This duty includes an obligation to eliminate or minimise public risks and a prohibition against directly or indirectly causing or encouraging a driver or another person, including a party in the CoR, to contravene the HVNL.
Transport activities
Transport activities include all the activities associated with the use of a heavy vehicle on a road. These activities include safety systems, business processes such as contract negotiation, communication and decision-making, as well as the activities normally associated with the transport and logistics sector, such as training, scheduling, route planning, managing premises, selecting and maintaining vehicles, packing, and loading.
So far as is reasonably practicable
So far as is reasonably practicable means an action that can reasonably be done in relation to the duty, considering relevant matters such as:
- the likelihood of a safety risk or damage to road infrastructure
- the harm that could result from the risk or damage
- what the person knows, or ought reasonably to know, about the risk or damage
- what the person knows, or ought reasonably to know, about the ways of removing or minimising the risk, or preventing or minimising the damage
- the availability and suitability of those ways
- the cost associated with the available ways, including whether the cost is grossly disproportionate to the likelihood of the risk or damage.
Effects of poor load distribution
Effects of poor weight distribution can vary depending on the vehicle type. Smaller rigid trucks, while still affected, are generally more forgiving due to the lower mass forces at play. When you step up to articulated vehicles and multi-trailer combinations, the affects soon multiply and can include:
- reduced dynamic stability
- increased crash potential
- reduced braking performance
- loss of steering control and Jack-knife
- increased driver fatigue
These can all be caused by incorrect weight distribution.
Circumstances where hazards may arise
Fleet operations where a large number of vehicles and trailers are being loaded each day can be at substantial risk if suitable managements systems are not in place and followed by everyone from the manager to the person loading the vehicle.
The modern freight task has changed a lot of the years to streamline operations to maximise productivity and fleet equipment utilisation. This often results in drivers having little, if not nothing at all to do with the loading process. Trucks loaded waiting for a driver to arrive to complete the journey, quick-hitching trailers often sealed with security tags, sees the drivers at times totally unaware of how the vehicle is loaded.
Multi-trailer combinations can be problematic if not adequately monitored
Example 1
Two local drivers are tasked with unloading trailers and then reloading for the next nights interstate run or change-over. One has the A-trailer, the other the B-trailer. Both trailers get unloaded then the drivers proceed to load them again.
The driver with the A- trailer loads, 6-pallets of toilet paper and then at another location, loads 6-pallets of breakfast cereal. He then returns to the depot and unhooks the trailer. The second trailer is loaded with 20 pallets of bottled water and 2 pallets of tinned dog food. He then returns to the depot and unhooks the trailer. The yard truck driver later connects the two trailers together to form a combination for the run that night by a sub-contracted tow operator. While each local day driver loaded completely safe and compliant loads on their trailers, the yard driver has just inadvertently created and very dangerous combination.
Unloading trailers and combinations in the incorrect order that was scheduled may also have an adverse effect on dynamic stability.
Example 2
A couple of years ago I was requested to road-test and review a new truck model for a media publication. The truck was a 6X4 prime mover with a single, tri-axle trailer loaded to a gross weight of around 38-tonnes.
The particular trailer I was towing was the same trailer (and load) that I had used on a previous road test review but for that road test it was used in a B-double combination.
The road test of the truck with the single trailer was in short, horrible! The truck exhibited a vagueness of steering that had me chasing it all day. It wandered wherever the road surface wanted to take it and was a bit like like trying to hold on to a wet fish, a constant struggle to keep hold of it. I eventually pulled over and inspected the load more thoroughly than the restraint check I did from the rear door of the trailer before I left.
Upon opening the curtains and viewing the load from the side, I noticed that the concrete barriers which were loaded two side by side along the length of the trailer centre line were not loaded at the very front of the headboard, instead they started the load about a metre back.
The result of a post drive weight check noted that the load had added an extra 500kg to the steer axle weight and was over the tare weight for the front axle. This explained why the steering was so vague.
This second example highlights an easily overlooked circumstance that can affect weight distribution and safety. This trailer was completely well behaved as a second trailer in a multiple combination, but a totally different beast connected as a single unit.
In conclusion, fleet managers, allocators, schedulers, and loaders, as well as drivers, all share a big responsibility in ensuring loads are evenly distributed across vehicles and trailers, not only at the point of loading but throughout the journey of the load in all its forms.
Potential hazards should be identified and control measures put in place to eliminate or minimize any risk. Training is also a crucial step in this process, particularly for inexperienced drivers and loaders.
