Crest of the 6% Grade with 44 Aboard
Thursday, 5:40 p.m. You are the only driver of a 40-foot coach carrying 44 band students and chaperones from Columbus to Marietta. It has rained all afternoon; the pavement is wet and the outside temperature reads 37°F, so there is no ice but traction is reduced. At the crest of the hill a sign reads "6% DOWNGRADE NEXT 4 MILES," with a second plaque: "TRUCKS AND BUSES 45 MPH." Your bus has an automatic transmission with a retarder, air brakes with automatic slack adjusters, and 118 psi on the gauge. Two cars are close behind you. The brake-check pull-off is 200 feet past the crest on the right. Ten minutes ago a chaperone asked whether people could stand in the aisle to stretch their legs. You are 300 feet from the crest.
1. What speed and gear do you want as you cross the crest, and what do you do about the chaperone's request? Explain the reasoning, not just the number.
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Target: roughly 35 mph, in a low gear, with everyone seated before the crest.
- The speed you carry onto the grade is the speed the brakes and retarder must manage for four miles. Braking energy rises with the square of speed, so 45 mph requires far more energy to shed than 35 mph.
- Wet pavement cuts the retarder's effectiveness because it works through the drive tires. Treat it as a helper, not the primary brake.
- The 45 mph posting is a ceiling, not a target. Traffic behind you does not obligate you to enter a downgrade too fast; let them pass at the pull-off.
- Have the chaperone seat everyone now, before the grade. A standing passenger becomes a projectile in any hard application or evasive move, and you lose the option of a firm stop.
- Confirm gear and retarder engagement at the crest, not after speed has built.
2. Halfway down you smell hot brake lining and the pedal feels slightly lower. What is happening, and what are your next actions?
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You are getting brake fade, and it must be treated as an emergency in slow motion. Heat from continuous light braking cannot escape, drums expand, and the same pedal pressure produces less stopping force.
- Get off the pedal. Use snub braking: a firm application to bring speed down 5-10 mph, then release fully so the drums cool between applications. Stay in the low gear and keep the retarder at its highest safe setting.
- If the pedal keeps falling or the smell worsens, stop at the next safe pull-off. The brake-check area exists for exactly this.
- Once stopped, chock the wheels rather than setting the parking brake on glowing drums, which can warp or crack them. Let them cool, feel for heat, look for smoke, and check for a dragging brake.
- Do not continue the descent on hope, and never roll a loaded bus in neutral to "save the brakes." If it cannot hold a safe speed, park it and call for a replacement.
3. A passenger complains that you are going too slowly and the two cars behind are tailgating. How do you handle the pressure?
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The pressure is real, but the grade does not care. Two cars on your bumper are a reason to be predictable, not fast. Hold a steady, slow speed, signal early for the pull-off, and let them go by at the brake-check area. A bus that speeds up to clear the way arrives at the bottom with hot brakes and no margin.
Tell the passengers the truth over the PA: "We're on a long downgrade; I'm holding a low gear and a slow speed on purpose." That converts a complaint into cooperation and discourages anyone from getting up.
If a tailgater will not pass, do not brake-check or wave them around. Maintain your speed, increase following distance to the vehicle ahead, and take the next safe turnout. Report aggressive driving to dispatch with a plate, location, and time if it continues. Your job is to get 44 people down four miles of 6% grade, not to satisfy a driver behind you.