Loading and mass limits

By the end of this topic you can

• You can explain the load restraint performance standards in plain terms.
• You can choose suitable restraint methods such as blocking and tie-downs.
• You can describe how mass limits apply to the vehicle and to axle groups.
• You can check and re-tension a load during a trip.
• You can explain why everyone in the supply chain shares responsibility for safe loading.

What you need to know and understand

• Loads must be restrained to withstand at least 80 percent of their weight pushing forward (0.8 g).
• Loads must also withstand at least 50 percent of their weight pushing sideways and rearwards (0.5 g).
• If friction is relied on to hold a load, it must also be secured against 20 percent of its weight lifting up (0.2 g), because bumps can unload friction.
• The NHVR Load Restraint Guide sets out accepted ways to meet these standards.
• Mass limits apply to the whole vehicle and to each axle or axle group. The vehicle's own GVM and the road access rules both limit what you can carry.
• Under the Heavy Vehicle National Law, people other than the driver, such as loaders, consignors and schedulers, also have safety duties. This is called the chain of responsibility.
• Penalties for overloading get more serious the further over the limit you are.

What the load must withstand

When a truck brakes hard, the load keeps moving forward. When it corners, the load wants to slide sideways. The performance standards describe how strong your restraint must be: able to hold 80 percent of the load's weight forwards and 50 percent sideways and backwards. These are minimums for normal driving, including emergency braking and swerving.

Friction alone is rarely enough. A bump can lift the load for a split second, and while it is light it can slide.

Ways to restrain a load

Use rated equipment in good condition. Check webbing for cuts and chains for damage, and protect straps from sharp edges with corner protectors.

• Blocking: placing the load hard against a headboard, gates or other solid parts so it cannot move.
• Direct restraint: chains, webbing or ropes attached from the load to anchor points, holding it in place.
• Tie-down: straps pulled tight over the load to clamp it to the deck and increase friction.
• Containing: using sides, gates or nets to keep loose items in.
• Covering: tarps or nets for loose loads such as soil, sand or green waste, so nothing blows out.

Staying within mass limits

Every vehicle has a GVM set by the manufacturer, and combinations have a GCM. On top of that, the law sets mass limits for axles and axle groups and may allow higher limits for operators in certain schemes or on approved routes. Mass and access rules have been under review, so always check current NHVR guidance or the rules in WA and the NT.

Spread the load so no single axle group is overloaded. Heavy items generally go low and close to the centre line. A load placed too far back can take weight off the steer axle and make steering light.

Checking the load on the road

1. Inspect restraints before you leave and walk around the whole vehicle.
2. Stop and re-check after a short distance, as loads settle and straps loosen.
3. Re-check at each rest break and after rough roads.
4. If anything has moved, stop safely and fix it before going on.

Common mistakes

• Relying on the weight of the load to hold it in place. Friction drops over bumps, so use proper restraint.
• Using worn or damaged straps. Inspect gear before every load.
• Loading the heaviest items at the back. Keep weight low and well forward of the rear axle group.
• Not re-checking straps after the first few kilometres.
• Assuming the loader is responsible for an unsafe load. The driver also has a duty to refuse or fix it.

Test yourself: Loading and mass limits

Answer each question, then read the explanation. Questions come in a random order each time.