GRADES:not school ones either!

Some of the greatest hazards of driving an 18-wheeler are steep mountain grades. These are hazardous because the weight of a truck (up to 80,000 lbs) and inertia make a truck want to go as fast as possible down a mountain while diminishing its ability to stop. A car, say weighing 7,000 lbs, has neough stopping power where the downhills are really not an issue. A truck "pulling" up a hill will just chug away at about 20 mph, but at the summit it is a whole different story. The truck needs to be in a low gear so to aid it from not picking up too much speed, then the brakes need to be applied every time the rpm's go up to the limit. This is called "stab braking." If the truck is in the wrong gear it is almost impossible to downshif in the downhill. The saying goes: "you can gown a mountain a million times too slow, but only once too fast." Now, in slippery road conditions the problem is much worse. Here, if the trailer brakes lock up, the trailer goes faster than the tractor causing a "jackknife" when the trailer comes around and slams into the tractor causing a rollover etc. In the middle of steep grades, states have found a way to try and avoid an accident in a last resort situation with a "runaway truck ramp." These are gravel or sand steep uphills that the driver would exit onto in the case that he/she has lost control. The truck hits it and, while sinking into it also hits a very dramatic uphill. These damage the truck but save the driver and other motorists lives. Ironically, states charge drivers a considerable amount of money to use these called a "reset fee," the cost of resetting the gravel after truck is towed out. In the East, the steepest grades are along the Appalachian range. In the West, it's a whole different world with grades double the steepness. Grades are measured by percentages. Typical Eastern grades are between 4% and 7%. In the West, like in the rockies and Sierras they can be as high as 15%.