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How to drive safely on gravel roads

More overland trips end in a gravel-road rollover than in any river, dune or rock. Most of these crashes happen on good, wide gravel roads, in daylight, on a straight or a gentle bend, when the driver felt confident. On gravel, speed and sudden steering roll vehicles.

Why vehicles roll on gravel

Loose stones act like ball bearings under the tyres. A rollover usually goes like this:

1. The driver enters a bend, a crest or a loose patch too fast.
2. The vehicle starts to slide.
3. The driver brakes hard, or steers hard back towards the road.
4. The tyres suddenly grip, or catch the soft edge of the road, and the vehicle tips.

Things that make it more likely:

• speed, above all;
• a high, heavy load, especially on a roof rack;
• wrong tyre pressures or worn tyres;
• tiredness, and long straight roads that make drivers fast;
• an unfamiliar vehicle, such as a rented camper with a rooftop tent.

Choose a safe speed

The safe speed is usually much lower than the legal limit. As a general guide only:

• on good, wide, smooth gravel in daylight, many experienced drivers keep to about 60 to 80 km/h;
• on corrugated, narrow or winding gravel, go much slower;
• on rutted, stony or sandy sections, 40 km/h or less.

Brake before the bend, not in it. Slow down while the vehicle is still straight, then drive through at a steady speed. Braking takes far longer on gravel than on tar.

Slow down and keep left before every crest. You cannot see the sharp bend, the washed-out drift or the herd of goats on the other side.

If the vehicle slides

• Do not brake hard.
• Ease off the accelerator smoothly.
• Look and steer gently where you want to go.
• Do not jerk the wheel back towards the road. Make small, smooth corrections and wait for the tyres to grip.

Keep both hands on the wheel, with your thumbs along the rim and not wrapped around the spokes. Leave stability control switched on, unless your manual says otherwise.

Dust

• Put your headlights on in daylight, so that others can see you through the dust.
• Drop back out of the dust of the vehicle ahead. If you cannot see, you are too close.
• When an oncoming vehicle passes, slow down and keep left until its dust clears.
• Overtake only where you can see far ahead. Often it is better to stop for a few minutes and let the dust settle.

Corrugations and drifts

Corrugations loosen bolts and break things. At some speeds the vehicle seems to float over them, but the tyres are touching the road less, so steering and braking are poorer. Keep the speed moderate and lower the pressures a little. Slow down before every dip, and in the rainy season, stop and look before you cross.

Animals

Expect livestock, game and people on foot. Kudu and other antelope cross at dusk and dawn. Where you see one animal, expect more behind it.

Not after dark

Plan every gravel day to finish before sunset. At night, animals and potholes are hidden, vehicles without lights are common, and many rental agreements limit cover for night driving. If the day runs late, stop at a farm or guest house. The camp booking can be changed. A crash at dusk cannot.

Brief your passengers

• Seatbelts on, all the time, front and back.
• Nothing loose in the cabin.
• Quiet at bends, crests and in dust.
• Anyone who feels that the vehicle is going too fast may say so, and the driver slows down.
• A stretch every two hours.

This guide is based on Chapter 4 of 4x4 Driving and Overlanding in Southern Africa.