2 years ago an Iowa DOT man was at one of our tractro club meetings and he told us the Feds wanted to make it manditory that every vehicle with a GVWR over 10,000 be required to have a DOT number. The problem they found out was that most 3500/350 trucks and large subrban style vehicles had GVWR over 10,000. So that would mean if you were a city slicker trying to look tough by owning a heavduty pickup truck, you would be required to have a DOT number displayed on the side of your vehicle so you could legally drive it to pick up a gallon of milk from the store and drop off the kids at soccer practice.
I know there's a lot of stupid out there in the law books, but at the same time I have seen a few accidents where some one tried to cut corners and it cost life. Example: not too long after I started college a high school girl was traveling between towns following a flatbed semi hauling crushed cars. The cars were not properly chained down and the chains gave and one of the squished cars came off the back and killed her instantly.
It's like one guy in our tractor club said at a show this past weekend, if people would just use common sense and not cut corners we wouldn't need all these regulations and the roads would be safer.