Wyoming CDL Permit Test - Tank

Distractions that can affect safe driving can be classified as physical (such as reaching for an object), mental (such as talking with passenger), or both (such as talking on a hand-held phone).

Always downshift before beginning to drive downhill. Forcing an automatic transmission into a lower gear at a high speed could damage the transmission and also lead to a loss of ability to engine brake. Drive at a speed that will allow you to control your vehicle without overusing your brakes. When determining a safe speed to drive, you should take into account the steepness of the grade, the length of the grade, the weight of your vehicle, road conditions, and weather conditions.

The service air line carries air and is controlled by either the foot brake or trailer hand brake. The service air line is attached to relay valves, which allow the trailer brakes to be applied quickly.

Rollovers can happen when a combination vehicle is turned too quickly. To help prevent the risk of rollover, it is important to keep the vehicle's center of gravity low by loading cargo as close to the ground as possible.

In general, vehicles carrying hazardous materials are required to display diamond-shaped warning signs on all four sides. These warning signs are called "placards."

Before a trip, be sure to inspect all couplings. There should be no space between the upper and lower fifth wheel.

A trailer tends to swing around, potentially resulting in a trailer jackknife, if its wheels lock up.