Semi Truck Accidents

Facts About 18 Wheelers

This page of our website reviews some common questions about 18 wheelers. If you or a family member have been injured in an accident with an eighteen wheeler, call our Law Firm at 1.800.862.1260.

1) Legal weight for an 18 wheeler:  The legal weight for an legally operating eighteen wheeler is 80,000 pounds or 40 tons. That is assuming that the truck is operating with no oversize or overweight permits. In comparison, the average U.S. automobile weighs only 5,000 pounds.

2) Length of a standard 18 wheeler: The average length of an 18 wheeler varies greatly depending on the type of cab they are driving. But the standard or overall average is 70-80 feet long. The length of an 18 wheeler's cab usually averages between 245" to 265" wheelbase. This is measured from the center of the rear wheel to the center of the steer.

3) Length of time needed to stop an average 18 wheeler: The average length of time it takes to stop an 18 wheeler is 40% greater than that of an automobile. Thes measurements are dependant on the weight of the trucks load, whether they are bobtailing, road conditions, weather conditions and other factors.  Trucks only have 10 brakes not 18.  Trucks manufactured now are required to have anti-lock brakes.

4) What does an eighteen wheeler cost? While there are numberous variables on the costs, the CAB of an eighteen wheeler usually ranges from $80,000 to $140,000 new. The trailers usually range from $30,000 to $70,000 new.

5) What is the "fifth wheel"? The 5th wheel is located immediately behind the cab of an 18 wheeler.  It is a large round metal plate above the drive tires that couples and secures the trailer to the truck.

6) How many gears does an 18 wheeler have? The most common amount of gears in an 18 wheeler today is 10 forward drive and 2 reverse drive gears. However, depending on the manufacture of the truck, some trucks have only 9,  some 10, some 13, some 15, and some 18 gears.

7) What is "bobtailing"? Bobtailing is a term used when a truck is driving without a hauling trailer attached. This can be very dangerous especially in wet weather, for the weight and optumim engineering is affected, which can cause the truck to lose control or its' footing.

8) What is the standard height of an 18 wheeler? The standard height of 18 wheelers is: 13' 6"

9) What Is A Tandem? A "Tandem" is a set of 2 tires on a tractor-trailer, side by side. This design is used for safety and redubdancy, in the event of one tire blowing out.  In such a case the other tires will continue to hold the trailer until the tire can be repaired.

10) What Is A Jack-Knife Accident? A " jack-knife" accident is when the trailer contacts the tractor by the trailer "coming around" on the driver. It is said that once a trailer exceeds a 45 degree angle, compared to the tractor, that a jack-knife is inevitable. This can be caused my many things.  This can happen on icy or wet roads but it can also happen on dry roads when the trailer is empty and the driver must brake hard. What will occur is trailer wheels start to skid and actually ends up moving faster than the cab is moving.

11) How Many Axles Does An 18 Wheeler Have? An 18 wheeler has a total of five (5) axles.


If you or a family member have been injured in an accident with an eighteen wheeler, call our Law Firm at 1.800.862.1260.

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