Federal law requires that most commercial routes (and all interstates) be able to withstand loads of at least 80,000 pounds with a 5-axle truck & trailer.There are numerous configurations of varying trailer lengths, multiple trailers, axle sets, and so on. The ones included here are the most commonly seen on American highways. And DO NOT laugh at my pitiful little truck drawings!

In most cases the maximum allowable gross weight is 80,000 pounds. States have the option of allowing more than this, but not less. These laws apply to all roads that are part of the Interstate System. This includes all interstates, most U.S. routes, and a number of state highways.

There was a time not too many years ago when each state had its own set of rules. You could be perfectly legal in one state, and get an overweight ticket ticket in the next one. The federal government stepped in back in the 70's to solve the problem. It was one of the few times in our history when government intervention turned out to be a good thing.

There are still some aspects where laws vary from state to state, but they are few and far between. It's worth noting that most weight violations are written for being over weight on an axle rather than being over the gross limit. It's also worth noting that the vast majority of these violations are minor. Being 300 to 500 pounds over weight on one axle (or set of axles), when that weight is spread out over anywhere from four to eight tires hardly constitutes a situation where damage is being done to the road surface. I'm not saying it's okay to run overweight, I AM saying that most citations written for weight violations are basically just revenue generators. As is typical of any level of government, it's about the money.

From my experience, most drivers who habitually run overweight are local guys. Log trucks, short-haul dump trucks, etc. They generally don't have to cross any state scales while loaded, and as such can pretty much break the law with impunity. Not so in my line of work.

A typical situation would be two or more small gravel hauling companies who bid on a job. They cut rates relentlessly until one of them finally gets the job. This stuff is generally hauled by the ton. So, to make up for the low rate (per ton), they simply load on more product. The logic is sound except that those heavy loads have many negative consequences. Aside from damaging the roads, the added weight increases the distance needed to stop the vehicle, which is a safety hazard. It's also hard on the truck as well, wearing it out well before its normal lifespan has passed. All in all a losing proposition.

Running long-haul generally requires that I cross at least a couple of state lines with every load, and as such I'll be encountering some state scales, too. It is therefore to my benefit to run legal. Unfortunately, there are a lot of situations where a driver can end up overweight. Here's a common scenario:

A refrigerated carrier (otherwise known as a "reefer") pulls into a produce dock during harvest season to get a load of lettuce. The empty tractor-trailer weighs about 35,000 pounds. Most large produce houses have onsite scales. The driver gets an empty weight, and the shipper loads him right to the limit. The guy leaves the produce house weighing about 79,800 pounds (as stated above, the weight limit is 80,000 pounds). The problem here is that to maintain moisture in the trailer, the driver is required BY THE SHIPPER to go to a nearby ice vendor. Here, another 1200 to 1800 pounds of crushed ice is blown across the top of the load. The ice will slowly melt, keeping the lettuce fresh and moist until it reaches your home a few days later. But, the driver is now grossing between 81,000 and 82,000 pounds. He's well over the limit, and the shipper will drastically cut the rate if he has to off-load some lettuce to make it legal, if he's willing to take it off at all. The threatened rate cut is large enough that the truck would be operating at a loss. The ticket, if the driver gets caught, is going to be even worse. This situation occurs literally hundreds of times per day across the country. It's distressingly common.

You'd be amazed at the sleaziness of some of the people who ship the fresh produce you buy at the store. I'm not referring to little mom & pop operations. They're by and large fine people. I'm talking about the big operations found in the major markets. Independent drivers are especially vulnerable to these tactics due to their often limited resources. Many drivers are hesitant to stand firm when confronted with this situation because they are afraid of losing the load, or perhaps even losing a customer.

There are other times when we load in an area where there is no place to weigh. This generally isn't a problem in a city, but in rural areas it can be fifty miles or more to get to a public scale. What if there's a state weigh station before the public scale? It's up to the officer at the weigh station. Some are common-sense people who recognize that the driver is blameless in this situation, while others don't bother with such trivialities as being considerate of other people. It's a crap shoot. I can generally look a load over and make the necessary adjustments, but it's still mostly guesswork without a scale. The problem here is getting the axle weights right. Simple math is all that's needed for the gross weight; I know what my tractor-trailer weighs, and the (hopefully accurate) load weight is listed on the freight bill.

Axle weights are adjustable. Most trailers have a "slider" which allows the driver to adjust the position of the trailer axles relative to the trailer's cargo area. Sliding them forward shifts weight off of the truck's rear axles and onto the trailer axles. Sliding them back does the opposite.

The fifth wheel, which is the device mounted on the frame of the truck that latches the truck to the trailer, also has a slider. Moving the fifth wheel forward shifts weight off the rear truck wheels to the steering axle, and sliding it back shifts weight from the steering axle to the rear axles. Trailer weight is not affected by moving the fifth wheel. It's often difficult to make precise changes when we're close to the limit because of the amount of weight shifted with each increment of a slider. This is generally 250-300 pounds with a trailer slider, and about 500 pounds per increment with the fifth wheel. There have been many times when I've had to return to a shipper and have them move the load around. Some places try to tell me that it's my problem (even though THEY loaded it). My normal response is something on the order of, "Get it right, or unload the damn trailer!" My bluff has been called a few times, but not often. If I end up with an empty trailer, so be it. I don't run overweight.

Compounding the problem is the fact of length restrictions. Different states have different maximum lengths. This is generally measured from the trailer's "kingpin" (this is the large steel pin that latches in the fifth wheel) to the center hub of the trailer's rear axle. However, some states measure from the kingpin to the center of the front axle, while still other states measure from the kingpin to the centerpoint between the rear axles (with a tandem-axle trailer) or the center of the axle (with a single-axle trailer). Confusing? Of course it is. It's MEANT TO BE CONFUSING. Confusion on my part leads to revenue for the greedy little bloodsuckers who make these laws.

If a load is loaded heavy to the rear, it's necessary for me to slide the trailer axles back to get the axle weights legal. But then I run the risk of being over-length. It's a very profitable racket for the states, generating tons of revenue every year in the form of fines layed upon drivers who were unable to satisfy both requirements. I can pick up a load in Texas bound for Los Angeles and be legal all the way to California, then get a ticket worth several hundred dollars because California only allows 40 feet from kingpin to rear axle. I should mention that in the above illustration, this trailer would be maybe 36 feet long. I'm using it here mainly just to save space (and to keep from having to draw another illustration - I'm such a bum!). The most common length for enclosed trailers nowadays is 53 feet. So, it's very possible to end up with the back of a load being 10 feet behind the trailer axles. With heavy freight, this can get complicated pretty quickly.

It gets even worse in states that enforce the "Bridge Law." This is a mind-numbingly complex system which allows varying weights depending upon the length of the tractor-trailer, the number of axles, and the space between the axles. I won't bog you down with the details. Suffice it to say that a chart to fully illustrate the bridge law formula would actually double the size of this page. No foolin'! It's almost as bad as the tax code.

Well, that about covers it. The bottom line is that 99% of us actually do try to run legal, even if it means putting up with abuse from shippers. I hope you've found this interesting. Feel free to drop me an e-mail with questions or comments. I'm on the road a lot, but I try to check the mail at least once per week. - Alan