Sizes, weights and limitations
Tractor trailers come in many different shapes and sizes. This all depends on the length of the trailer and the length of the cab itself. Most will measure from 70 to 80 feet long but can go as long as 150 to 200 feet long. Those 150 to 200 feet along are specially designed over sized loads like wings for wind mills that go on these wind farms. They require escort vehicles and will require much more room than a standard sized tractor trailer when making turns and other maneuvers.
My particular tractor trailer combination measures 75ft from nose of tractor to end of trailer. This is pretty much a typical configuration. The turning radius is approx 100 to 200 ft. This means they need that much room when turning in parking lots or other tight maneuvering situations.
The legal weight for tractor trailer combinations is up to 80,000. This includes weight of tractor trailer and product. Weights can exceed that only with special permits.
Stopping and following distances
Contrary to popular belief, a tractor trailer does not have a brake on each wheel. I E an 18 wheeler does not have 18 brakes. There are 2 brakes per axle. Generally speaking, there are 5 axles on tractor trailers. Each axle has 2 brakes on it. Therefore a 5 axle truck will have 10 brakes. If the truck is fully loaded to 80,000lbs, that means stopping power of 8,000 lbs per brake. That would be the equivalent of stopping two 4,000 lbs cars with just 1 brake!
A fully loaded semi traveling at 60 mph requires 300ft to safely stop. That is the length of a football field. This length will increase as road and weather conditions decrease. Cutting of trucks can become very hazardous to your health.
Following distances
Although there are no laws stating how far cars must follow behind a semi, I would like to present some thoughts for consideration.
Blown tires:
Truck tires are made of hard rubber with steel belts inside. They are filled to approx 110lbs of pressure and can weigh over 50lbs when fully inflated. When they blow, there is a tremendous amount of force released.
Example 1: A mechanic, who weighed 150lbs, was inflating a recapped tire. When it blew, the force of it slammed him into the wall 20 feet behind him. (If the dumbass would have followed established safety procedures, he probably would not have been hurt).
Example 2: I was traveling on an interstate in Illinois when a trailer tire blew out. The mud flap (5lbs) and its metal hanger (5 lbs) elevated about 10 to 15 feet in the air at 65mph. if someone had been tailgating; I hate to think what kind of damage would have been done. There have been accidents recorded where tire treads have flown through windshields.
Falling debris:
Truck drivers cannot safely remove snow and ice from on top of their trailers when the trailer roof is 13ft 6in off the ground.
A good safe following would be a minimum of 1 car length for every 10mph. Keep in mind that this should be increased during bad weather and times of reduced visibility.
Stop signs and stop lights:
It’s a good idea to stop about 10-15 ft away from a semi when necessary to come to a complete stop, especially when on an uphill. When starting out, a semi may “drift” or roll back wards when releasing the clutch and engaging the throttle. Good truck drivers know how to compensate for this. Not all truck drivers are good drivers!
By the way some states do have laws requiring how far semis are supposed to be following. In Iowa, it’s 300ft. In Wisconsin, it’s 500 ft. It’s really scary to me when I see trucks following much closer to vehicles then they should be.
Speed limiters/inhibitors. (Commonly referred to as “Governors)
These are computer controlled devices that limit the speed of a truck when heading down a flat stretch of road. A vast majority of companies use these on their company trucks not only as a way of controlling vehicle speed, but also as a fuel saver. Companies themselves generally dictate what speed these are set at. Some companies out here have theirs set as low as 58mph while others are set as high as 75mph. a vast majority of the trucks are set at 62 to 65mph. This can create problems when traveling in states where the posted speed limit is higher than the truck is capable of doing. If you are traveling in a state where the speed limit is 70miles per hour on the interstate and the truck in front of you is only going 65, chances are that is a fast as he can go. If weather and traffic conditions permit, please continue on at the posted speed limit. Too often cars will fall in line behind the slower truck for no apparent reason. When enough cars and trucks do this, this creates an unnecessary traffic back up and can become a serious safety issue. Some states also have split speed limit laws. Take Michigan for example. Cars are allowed to travel 70mph on the interstates while trucks are only allowed to go 60mph.
Slow moving vehicles:
Because trucks are considered slow moving vehicles, they are often restricted to the right lane of travel on an interstate. This allows for the fast more agile vehicles to safely pass on the left. This is especially true in mountainous/hilly terrain. Often times, trucks will travel uphill or downhill with their 4 way emergency flashers activated. In some states, it’s the law. Therefore, as traffic and weather conditions permit, safely pass them on the left and continue on your way.
Trucks carrying hazardous material:
Hazardous material (HAZMAT) Haulers can be identified by the square on point, triangle shaped placards that are supposed to be displayed on all four sides on the vehicle. By law these vehicles are required to stop at ALL railroad crossing, put on their 4 ways flashers and safely proceed once they have verified there are no trains coming. Some states like Wisconsin provide slow down/speed up lanes just for this purpose. Most states do not. Please be patient with the trucker. The life they save, by following the law, could be yours.
Happy motoring……stay tuned……………..
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