18-wheelers
MUST make wide turns
By: James R. Davis
I'm sure that virtually all of us have seen an 18-wheeler sporting a sign that reads something like "Makes wide turns".
When on the major highways and freeways, those signs don't mean much and quickly fade from our consciousness. We deal with those big rigs with respect and caution anyway, because we all know
- they are BIG,
- they have a lot of air pressure in their tires that can be serious trouble if they blow (so we spend as little time near them as possible),
- they can capsize if going too fast in a curve,
- their drivers, though some of the best and most capable anywhere, can be on a long haul and groggy/tired, and
- almost incidentally, they make WIDE TURNS.
But that last fact is not incidental. That, because 18-wheelers don't just travel on the major roads. They MUST, from time to time, travel on the surface streets, and sometimes even travel in residential areas.
An 18-wheeler has very little trouble handling left turns (except in countries where traffic flows on the left side of the road). But right turns are difficult for them.
Taking notes? Jot this down: 18-wheelers MUST make wide turns, it's not optional.
If an 18-wheeler had a tractor that was not articulated with its trailer, it could not make a normal right turn at all - safely. Whenever such a rig tried to make a right turn the trailer's rear wheels would 'cut the corner' running up and over the curb in the process. Even if the tractor and trailer are articulated, turning right WILL result in the trailer's rear wheels 'cutting the corner' UNLESS THE TRUCK MAKES A WIDE TURN. (This is why the curbs at the corners of streets that intersect with freeway feeder roads are so often destroyed - 18-wheelers literally crush and break them.)
Just like what is available for motorcyclists, states provide truckers with Commercial Motor Vehicle Driver Handbook. This is what is said in Texas's handbook about trucks and buses making right turns.
Notice that there is no law that says that trucks cannot make wide turns. This handbook provides suggested best-practices about turning right. Because long rigs MUST make wide turns.
Look closely at the two diagrams. See that Figure 2-12 ("Don't Do This") shows a path of travel that swerves to the left BEFORE the right turn - possibly into oncoming traffic - but if you look at Figure 2-1 ("Do This") you will see that the vehicle DOES turn into oncoming traffic - because it makes a wide turn in any event.
So, if you are traveling near an 18-wheeler that has its right turn blinkers flashing, move as far to the left of it as you can as you pass it. If you are approaching an intersection where a truck might have to turn right into that intersection and toward you, move as far to the right as you can.
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(James R. Davis is a recognized expert witness in the fields of Motorcycle Safety/Dynamics.)
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