CDL Combination Vehicles TestDriving Combination Vehicles SafelyMedium
A commercial driver is operating a combination vehicle on a four-lane highway and plans to exit using an off-ramp that curves sharply to the right. To safely navigate this exit, what should the driver do?
- AMaintain highway speed until entering the off-ramp, then apply firm braking.
- BUse the engine brake only to slow down once on the off-ramp.
- CBegin braking gently in the rightmost lane of the highway before reaching the off-ramp, then maintain a reduced, steady speed through the curve.
- DIncrease speed slightly to maintain momentum through the curve, then brake after exiting the curve.
Show answer & explanationAnswer & explanation
Correct answer: C. Begin braking gently in the rightmost lane of the highway before reaching the off-ramp, then maintain a reduced, steady speed through the curve.
Combination vehicles, especially when loaded, have a higher center of gravity and are more prone to rollovers on curves. Braking gently and reducing speed *before* entering the curve allows the driver to maintain control and a steady speed through the curve, minimizing centrifugal force.
Why the other options are wrong
- A. Braking sharply while already in a curve greatly increases the risk of rollover for a combination vehicle.
- B. Relying solely on the engine brake might not provide sufficient braking force, especially if the curve is steep or the vehicle is heavily loaded, and it doesn't allow for proper speed adjustment before entering the curve.
- D. Increasing speed through a sharp curve is extremely dangerous and significantly raises the risk of a rollover.
Safe Curve Negotiation (Off-Ramp)
Reduce speed before entering a curved off-ramp with a combination vehicle, then maintain a steady, controlled speed through the curve.
- Combination vehicles are prone to rollovers on curves.
- Brake before the curve, not in it.
- Maintain a steady, safe speed through the curve.
Memory trick: Slow before the Curve, Steady through the Turn.