Skids, Rollover Prevention, and Curve/Ramp Handling
Rollover is the tanker's signature crash, and exam items here test whether you slow down before the geometry - not in the middle of it.
Why tankers roll
A cargo tank carries its weight high and, when part full, carries a moving weight. In a curve, centrifugal force pushes the load outward; side slosh adds to it; the combination unloads the inside tires. The rollover threshold is lower than a van's because the center of gravity is higher and the load is not fixed.
Curve and ramp technique
- Choose a safe speed before entry, while the vehicle is still straight and stable.
- Hold steady throttle through the curve; do not brake hard or lift abruptly mid-curve.
- Accelerate only after the vehicle has straightened.
- On ramps, ignore the fact that the posted advisory number feels comfortable in a car.
- Make one smooth steering input rather than a series of corrections.
Recovering a skid
- Rear-wheel skid: steer in the direction of the skid; the real danger is overcorrecting and overbraking.
- Front-wheel skid: release the brakes and steer straight ahead until traction returns.
- If you must brake, do it on the straight approach, not in the middle of the turn.
Worked example
The ramp from an interstate to a state route is marked 30 mph. A driver carrying a partly filled smooth-bore tank enters at 30 and has to brake when the curve tightens. The load sloshes outward, the inside tires unload, and the truck leans hard. The correct plan is to slow well below the advisory speed on the straight approach, enter with gentle throttle, and hold it through the curve.
Traps that cost marks
- Treating the posted advisory speed as a target.
- Braking mid-curve to fix a fast entry.
- Overcorrecting a small rear-wheel skid into a rollover.