The main idea is that braking relies on friction between the tires and the road, which depends on how much load each tire carries. When weight is uneven, some wheels have less normal load, so they can generate less friction before their grip is reached. That means those wheels contribute less to slowing the vehicle, and the overall braking effort isn’t as effective as it could be. At high speeds this is especially problematic because small losses of grip become more significant and weight transfer during braking can worsen the imbalance, further reducing traction on the lighter wheels. The net result is a longer stopping distance. Keeping cargo evenly distributed helps maintain balanced grip across all wheels, improving braking performance.

The key point here is how long the dangerous goods training certificate stays valid. For drivers who carry dangerous goods, the certificate has a five-year validity. After five years, you need to complete periodic refresher training to renew it, ensuring you stay up to date with current rules, packaging and labeling requirements, segregation, and emergency procedures. Shorter periods (like one or two years) would be overly frequent, while a much longer span (like ten years) could allow outdated practices to slip in. So five years is the correct timeframe.

The main idea is that you must leave enough space to stop safely if the vehicle in front suddenly brakes. For a heavy goods vehicle, this space needs to be larger than for lighter vehicles because weight increases stopping distance and your ability to stop quickly is reduced. In good conditions, a two-second gap behind the vehicle in front is the minimum you should aim for. This gives you enough time to react and start braking, and it works as a simple, reliable rule. You must increase that gap when you’re traveling faster or when conditions are not ideal—slippery roads, rain, wind, reduced visibility, or any additional hazards all require more distance to stay safe. A practical way to apply it is to pick a fixed point on the road. When the vehicle in front passes that point, start counting seconds. If you reach the same point before two seconds have passed, you’re too close and should increase the gap. So, the safest, best-fitting choice is to keep at least a two-second gap in good conditions, and enlarge it as speed or conditions worsen.

The key idea is using a physical restraint that stops the wheels from turning. Placing chocks under the wheels provides a solid barrier that prevents any rolling, which is exactly what you need to stop movement when piggyback transporting, especially on slopes or during loading and unloading. Chocks pressed snugly against the tyre and ground stop the vehicle from moving even if there are vibrations or a slight incline, making them a reliable, passive restraint. Rope between the vehicles might help as an extra measure, but it isn’t enough on its own because a rope can slacken or break and won’t stop wheel rotation. Covering the vehicles (sheeting) doesn’t prevent movement at all, and driving in pairs isn’t a method for immobilizing the load.