A commercial driver is operating a tall box truck along a two-lane rural highway with a pronounced center crown. Why does driving on this crowned roadway increase the danger of an overhead collision with roadside trees or utility poles?
- The roadway slope causes the top of the vehicle to lean toward the shoulder, placing the upper body closer to roadside obstacles.Answer
- BThe lateral road grade causes severe rear-wheel off-tracking that automatically forces the tractor's steer axle upward.
- CThe slope shifts the cargo center of gravity to compress the outer suspension springs, substantially increasing the vehicle's total measured height.
- DThe reduced traction on the crowned slope increases required braking distance, forcing the vehicle to slide upward into overhead utility wires.
Answer
The roadway slope causes the top of the vehicle to lean toward the shoulder, placing the upper body closer to roadside obstacles.
On crowned roadways, the pavement slopes downward from the center toward the shoulder. This tilt causes tall commercial vehicles to lean to the right, pushing the uppermost part of the trailer or cargo body closer to roadside obstacles such as tree branches, signs, and poles that would otherwise clear a level vehicle.
Step-by-Step Solution
Key Concept
Overhead Clearance and Vehicle Tilt on Crowned Roads
Estimated Time:45s