Vehicle Loading, Mass Limits and Dimensions
Domain 4, Vehicle Loading, Mass Limits and Dimensions, tests whether the driver can calculate payload, distribute weight legally and secure a load for Cameroonian roads. The exam links loading to axle limits, bridge restrictions and vehicle stability, not merely to whether the truck can move.
Core rules
- Know the difference between kerb mass, gross vehicle mass (GVW or PTAC), gross combination mass and payload. Payload is GVW minus kerb mass; it is not the same as the load ticket weight.
- Axle limits apply separately. A load placed too far back can overload the drive axle and trailer axle even when total mass is legal. Spread dense loads over the deck and over the axles; never load against the tailgate.
- Common enforcement thresholds in Cameroon and the CEMAC region include width around 2.5 m, height around 4 m, rigid length around 12 m and articulated length around 16.5 m, with gross and axle limits checked at weighbridges. Always confirm the current arrêté and any route permit, because bridges and urban roads carry lower limits.
- Secure loads with rated straps, chains or tarpaulins; use chocks for coils and drums. The load must not project dangerously, obscure lights or plates, or spill. Abnormal loads need a permit and possibly escort.
Worked example
A three-axle rigid truck has a kerb mass of 9 t and a GVW of 26 t. The legal payload is 17 t. A loader puts on 18 t of cement and moves it to the rear. The truck is 1 t over GVW and probably over the rear-axle limit. The driver must not sign the ticket and depart; the load must be reduced or redistributed, then reweighed. If the rear axle is still over its plated limit, the vehicle stays parked.
Traps
- Equating payload with GVW and believing a 26 t truck can carry 26 t.
- Checking only total mass and ignoring axle loads.
- Assuming volume equals weight; sand, cement and steel are far denser than maize or empty containers.
- Forgetting that fuel, water, passengers and the spare wheel count toward mass.