Found on steep downgrades, escape ramps use a long stretch of soft material such as gravel or sand, sometimes on an upward slope, to bring any vehicle that has lost its brakes to a stop. They are not reserved for tankers or combination vehicles.
Selecting a low gear before the descent lets engine compression and friction absorb much of the vehicle's energy, so the service brakes are used less and are less likely to fade. Shift down before you start downhill, and do this with an automatic transmission too.
Gravity pulls a vehicle downhill, so on a long grade it keeps gaining speed unless you hold it back. Pick a low gear before you start down and let engine braking help keep the speed under control.
A truck pictured on a slope with the figure 8% warns of a steep downhill stretch where the roadway falls roughly 8 feet over every 100 feet. Before starting down, shift into a lower gear so the engine helps hold your speed in check.
Brakes that overheat, often from long or heavy braking on a downhill grade, lose much of their ability to stop the vehicle. Letting off the pedal for a moment will not cure the problem, and disc brakes can fade just like drum brakes; relying on a lower gear for engine braking on grades helps prevent it.
Modern trucks have streamlined shapes and low-friction parts, so very little drag holds them back on a downgrade. That is why they usually need a lower gear going down than going up, and coasting in neutral is dangerous because it gives up engine braking.
Brakes slow a vehicle by turning its motion into heat through friction, so extra weight or speed means extra heat for them to absorb. That heat does not add stopping power; overheated brakes weaken and can fade, so brake early and keep plenty of space ahead.
Escape ramps are built along steep downgrades so that a vehicle whose brakes have failed, or that is moving too fast to control, can leave the road and come to a stop, often in deep loose gravel or sand. They are not limited to any particular type of vehicle.
Press the brakes hard enough to feel a definite slowdown, let off once you are 5 mph under the safe speed, and brake again only after speed has climbed back to it. Brief, separate applications like this keep the brakes from overheating and fading.
Brakes that have faded from heat will not come back from pumping, and by then it is usually too late to get into a lower gear. Your best chance is an escape ramp or, if there is none, the least dangerous way out, such as an open field or a side road that levels off or climbs.
Constant hard braking builds heat that lowers the friction of the brake linings and makes the drums expand, a condition called brake fade that can leave the brakes unable to stop the vehicle. On long downgrades, use a low gear and engine braking so the service brakes do not overheat.
Choose a low gear before starting down so engine compression holds your speed back; the service brakes should only supplement engine braking, which keeps them cool enough to work when you need them. The parking brake is not meant for slowing a moving vehicle.
When brakes fail on a long downgrade, you have to rely on something outside the vehicle to stop it, and escape ramps are built for exactly that job. Pumping the pedal is unlikely to bring the brakes back, and turning off the engine only takes away engine braking.
Brake firmly enough to feel a clear slowdown, let up once you are roughly 5 mph under your safe speed, and brake again when the speed climbs back to it. Short, firm applications combined with engine braking keep the brakes from overheating and fading, which light, steady braking would cause.
Fade sets in when brakes get so hot from hard or constant use that they lose stopping power. Brakes that are out of adjustment add to the problem, because the properly adjusted ones must do extra work and overheat sooner.
Escape ramps exist to stop out-of-control vehicles safely, so a tanker whose brakes have failed should use one if it is available. Whether the tank has baffles does not matter.
Every question in this set has its own page with the correct answer and an explanation.
