Load and Mass Requirements
The core idea
Every heavy vehicle has limits on how much it can weigh and how that weight is distributed. Overloading is one of the most heavily enforced areas, and the exam tests both the rules and the practical checks.
Concepts you must know
- Gross Vehicle Mass (GVM) and Gross Combination Mass (GCM): the maximum permitted weight of the vehicle (or vehicle plus trailers) including load.
- Axle and axle-group mass limits: weight must be spread so no axle or group exceeds its limit. A load can be under GVM but still overload one axle.
- Load restraint: loads must be secured so they cannot move, fall or be dislodged. The performance standard requires restraint against forces in all directions; the common rule of thumb is restraint capable of withstanding 80% of the load's weight forward, 50% sideways and 50% rearward.
- Dimension limits: height, width and length limits apply, and loads must not project dangerously. Overhanging loads need warning devices.
- Mass management: weighbridges and on-board scales help verify compliance before departure.
Traps in questions
A classic trap is a load that is legal by total mass but illegal because one axle is overloaded. Another is confusing GVM with GCM, or forgetting that restraint must handle sideways and rearward forces, not just forward.
Rule of thumb
Check three things every time: total mass, axle/group mass, and restraint in all directions. If any one fails, the load is non-compliant.