Bridge Deck at 28 Degrees
At 06:10, the temperature is 28°F and freezing drizzle is falling. A driver is pulling a 65,000-lb box trailer on a two-lane US route posted 45 mph. The pavement looks wet, not icy, and the tires are throwing spray. Three cars are following about two seconds back. Three hundred feet ahead, a bridge deck has a dull sheen; the spray from the truck's tires seems to stop at the bridge approach. A salt truck is visible a half mile beyond the bridge, but no plow has run this section. The driver is 20 minutes from a 07:00 pickup and has cruise control set at 45 mph. The truck has an engine brake and automatic traction control. The shoulder is narrow with a ditch on the right.
1. What clues suggest ice on the bridge, and what should the driver do in the next few seconds?
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The clues stack up: 28°F, freezing drizzle, a bridge deck that looks shiny, and spray that seems to stop at the bridge approach. Bridges lose heat from below and freeze before the road surface. The driver should cancel cruise control now, slow gently before the bridge, and pick a speed that allows a stop within the visible distance. Do not brake hard on the bridge. Increase following distance well beyond two seconds, turn off the engine brake because it can break traction on the drive wheels, and keep steering inputs smooth. The salt truck beyond the bridge does not mean this deck has been treated.
2. If the tractor begins to slide or jackknife on the bridge, what inputs should the driver use?
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If traction breaks, ease off the throttle and avoid hard braking. If the wheels are locked, release enough brake pressure to let them roll again so steering returns. Steer gently in the direction the driver wants the front of the truck to go; do not saw the wheel or overcorrect. With a trailer, a small correction is usually enough, and a hard correction can start a jackknife. Once the truck is straight and rolling, continue at low speed or stop in a safe place. Automatic traction control helps, but it cannot create grip on ice.
3. Should the driver continue over the bridge and to the pickup? What communication and alternatives matter?
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The driver should not assume the bridge is passable just because traffic is moving. If visibility and surface conditions do not allow a safe crossing, stop before the bridge in a safe spot, call dispatch, and wait for treatment or a road report. If crossing, use a low gear and steady, light throttle; no cruise, no engine brake, no sudden lane changes. Continue to the pickup only if conditions improve and the driver can maintain a safe speed. Being 20 minutes out is not a reason to cross an icy deck at 45 mph, and the narrow ditch on the right limits recovery space if the truck slides.