Stopping Distance Under Load

Speed & Stopping Distances gave the tools; this lesson loads them up. Braking distance is set by kinetic energy, which the brakes must convert to heat — and kinetic energy scales with mass as well as speed². So more mass means proportionally more energy to dissipate, over more distance, through brakes that were sized for less.

The figure: a heavily overloaded vehicle can need on the order of 40% more braking distance than the same vehicle at legal weight. Apply it to the stopping table: an 80 km/h dry stop of about 65 m stretches toward 90 m; the same stop in the wet, already around 97 m, stretches further still.

Now stack it with the other multipliers. An overloaded vehicle, on worn tyres, in the wet, on a descent, is combining four independent distance-multipliers at once — which is precisely the profile of a loaded pickup or lorry losing control on a rainy escarpment.

That's the framing to carry through the module: overloading isn't a separate risk from stopping distances — it's a multiplier on them.