Explainers

Runaway truck ramps use deep loose gravel to slow a truck with faded brakes. Learn how they work, what to do if you use one, and how to avoid needing it.

Tandems over? Pull the tractor forward with trailer brakes set. Here's why that moves weight to your drives, and how to slide safely and legally.

Semis use air brakes because the truck makes its own air, small leaks can be out-pumped, trailers hook up easily, and spring brakes act as a backup.

The kingpin drops into the fifth wheel jaws and a spring lock wedges behind them. Here's how it works and the checks that prove the trailer is coupled.

Idling a diesel for half an hour is mostly a myth. Learn what really warms a cold engine: block heater, short idle, gentle driving, winter fuel.

The Kenworth W900 debuted in 1961 and kept its long hood and boxy grille for 60+ years. Here's why drivers still want one, and what it costs in wind.

Side skirts cut drag under a trailer and typically save a few percent of fuel at highway speed. Here is the math, the catch, and who benefits.

The 11-hour rule counts driving only. The 14-hour rule is a window that never pauses. Here is how both work, plus the 30-minute break.

A reefer holds temperature, it doesn't create it. Learn how insulation, airflow and the unit's own fuel tank keep freight cold for days.

DEF is diesel exhaust fluid, a urea-and-water mix sprayed into the exhaust to cut NOx. Without it, a modern diesel truck can derate and lose power.

A standard 18-wheeler spreads an 80,000-pound legal load across five axles so no axle or tire is overloaded. Here is how the math and the duals work.

A Jake brake opens the exhaust valve at the top of the compression stroke so the engine drags the truck down a grade and your service brakes stay cool.