Loads, Vehicle Weights, and Safety Responsibilities
Weight limits and load distribution
Every commercial driver must understand weight limits. Alberta regulates axle weights, gross vehicle weight, and gross combination weight, and questions will test the idea that overloading any single axle or tire is a violation even if the total weight looks legal. Know the terms: gross vehicle weight rating (GVWR) is the manufacturer's maximum for the vehicle; gross axle weight rating (GAWR) is the maximum for an axle; tare weight is the empty weight; and payload is the difference between the two. Loads must be distributed so no axle or tire is overloaded, and the steering axle must retain enough weight for control.
Securement
Cargo must be secured so it cannot shift, spill, or fall. Use appropriate tiedowns, working load limits, and edge protection, and check the securement again after the first part of the trip. A load that shifts changes the centre of gravity and can cause a rollover or loss of steering control. Know that aggregate working load limit must meet or exceed the weight of the load, and that covers and tarps must be secure.
The traps
- Total weight is legal, so the load is legal. False: a single overloaded axle is still a violation.
- A heavy load on the rear axle improves traction. It may, but it can unload the steering axle and destroy steering control.
- Securement checked once is enough. Recheck after starting out and at stops.
- Height, width, and length limits. Know that oversize loads need permits and that height clearance matters.
Worked example
A truck has a tare weight of 9,000 kg and a GVWR of 24,000 kg. The maximum payload is 24,000 minus 9,000, or 15,000 kg. If a 14,000 kg load is placed too far back, the rear axle may exceed its GAWR even though the total is under GVWR. The fix is to move the load forward until each axle is within its rating while keeping enough weight on the steering axle.