Semi Quiz | How Much Do You Know About 18 Wheeler Heavy Duty Trucks?

Posted by on 14 March 2016

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If you're a professional trucker or fleet manager, you undoubtedly know almost everything there is to know about heavy duty trucks. So why not take this "semi quiz" and see if you score 100%. Or share the quiz with your non-trucking friends. You might even learn a new tidbit of 18-wheeler trivia.

Heavy Duty TrucksWhy is a big rig called a "semi"?

The truck itself is called a tractor. It has the power and traction to pull a trailer. Because trailers simply follow the truck, most of them have an axle and wheels only at the back end. These are semi-trailers, as opposed to full trailers that have axles and wheels at both ends. The front of a semi-trailer attaches to the tractor via a 5th-wheel type hitch. Or sometimes the front end is supported during transit by a detachable dolly. Semi-trailers have retractable legs to keep them stable when they are uncoupled.

How big are truck engines?

A heavy duty truck engine is equivalent to several car engines. For instance, today's Cummins lineup includes engines that run from 320 hp to 605 hp. Detroit Diesel engines range from 350 hp to 600 hp.

How long does an engine last?

Truck engines are designed to run as many as a million miles. And they're designed to be rebuilt. Their longevity comes mainly from the fact that heavy duty trucks run long hours at higher speeds. This causes much less wear and tear that the kind of stop-and-go driving passenger cars and commercial delivery vehicles must endure.

How much can an 18-wheeler haul?

A semi's payload depends on the engine size, trailer size and configuration. Although a "semi" may consist of just one tractor and trailer, or there may be two trailers. If the trailers are both full size, this is called a turnpike double. If the second trailer is smaller, the configuration is called a Rocky Mountain double. In some states, triple trailers are allowed on major freeways. Regardless, throughout the US heavy duty trucks are not allowed to haul more than 80,000 pounds.

In remote areas of Australia, truckers can haul four trailers at a time, called a road train.

How much distance does a semi need to stop?

An 18-wheeler is long and very heavy, so it requires much more distance for braking than a passenger car. Depending on the truck's speed, that might be as much as two football fields. Stopping takes even longer on smooth roadways, because there isn't much tire resistance.

What does "jackknife" mean?

A "jackknife" is when a tractor and its trailer wind up at a 45-90o angle to one another. The position looks like the partially folded-out blade on a pocket knife, and it makes forward travel impossible. This can happen when roads are slippery, if a driver heads into a turn too fast or swerves to avoid something. A jackknife can cause the rig to roll over. To avoid a jackknife, big rigs can only make wide turns. A roadway would have to be 55 feet wide (the equivalent of four lanes) to make a U-turn.

Which state has the most 18-wheelers registered?

You can register your semi in any state, but California, Florida and Texas are where a full third of American heavy duty trucks call home.

What's different about driving a semi in Europe?

For one thing, British truck drivers are not allowed to smoke inside their truck's cab. European semis are also equipped with speed limiters that make it impossible to travel more than 56 miles per hour.

So how did you do? What other trivia about heavy duty trucks can you add to the list?

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