As you no doubt have observed, big trucks accelerate slooowly, from a standing start or in motion. My truck is no exception and because it has a relatively small engine block with less power, gets up to cruising speed more slowly than some other trucks on the road.
The important thing to note is that its cruising speed is governed (restricted electromechanically) at 65 miles per hour (actually at a small fraction under 65 mph). It is leased by the company I drive for and the company has chosen that setting as the best compromise between safety, speed and fuel economy. My truck’s 65 mph cruising maximum is the posted limit on many highways and is at least serviceable on the higher speed highways.
Governing is quite common among trucking companies. Other company trucks are governed at faster speeds than mine, and some companies and owner operators may choose not to govern their trucks. Where safe and lawful, many truck drivers can travel at significantly greater speeds, as fast as the fastest personal vehicles on the flats and can pass slower vehicles much more easily than I. In good conditions fast trucks will expose slower personal vehicle drivers to risk zones for smaller periods of time than my truck will.
One important exception to my truck’s speed restriction is when driving downhill. The truck will coast under its weight at higher than governed speed and I let it go up to the legal limit when it is practical and safe to do so. This helps to improve fuel economy and minimize freight delivery times. If you pass me going downhill I would like you to keep pulling well ahead of me, even more so than on level ground. This keeps you and me safe in case you encounter some emergency and I have to brake and/or take other evasive action. (For more information, see the Risk Zone: Close and Directly in Front of My Truck tip.)
The cruising restriction can be an irritant to personal vehicle drivers when I am passing another vehicle traveling at a slightly lower speed. My truck has only a very small “pedal override” (slightly faster speed than cruise via stepping on the fuel pedal), so I can nudge my truck past the other vehicle at just slightly faster than cruising speed. The passing process can seem agonizingly slow, both to me and other drivers behind me. This is probably the situation that most severely tries the patience of other drivers. We cover this subject in more detail and things you and I can do to minimize the inconvenience in the Passing Me and Passing You chapters.
When in front of a truck, pull and stay far ahead when practical, safe and lawful, and even farther ahead when driving in front of it downhill.
Please be patient when behind a truck that is slowly passing another vehicle—the driver is doing the best he can.