As hazardous as they are disgusting
Let's set the stage. You are a long-distance trucker. You are also (for reasons which will soon become clear) male. You have been up for twenty hours straight, probably on meth. Also you have been drinking a lot of coffee and Gatorade and Red Bull to keep awake.
No matter what, you have to keep on driving. But guess what? You also have to pee.
What's a guy to do?
That's right! Pee into one of the empty Gatorade bottles that litter the cab of your truck. Then cap that bad boy, and throw it out your window. That's a trucker bomb.
As convenient as this must be for the truckers, someone has to clean up all those Gatorade bottles full of urine. Highway clean-up crews are pretty tired of having to pick up someone else's pee bottle, believe me. A lot of clean-up crews are volunteer organizations who operate out of a sense of civic pride. If they quit cleaning up the highways, we will soon be up to our ears in discarded McDonald's wrappers and pee-filled soda bottles.
Clean up is also provided by each state's Department of Transportation. In the state of Utah alone, the DOT costs the taxpayers between $2 and $3 million dollars a year for highway clean-up. And their maintenance crews are handling an estimated 20,000 urine bottles a year. One small county in Washington State counted 2,666 bottles of urine over the course of a year. (As well as "67 feces covered items not including diapers." Yowza.)
This human waste is technically a biohazard. It's dangerous to have people cleaning it up, and it's difficult to get rid of. Also, it's super gross. If you have the bad luck to be mowing the shoulder on the wrong stretch of highway, when the mower blades hit the bottles "they explode. The operator ends up wearing this stuff."
Another problem is, a lot of people are under the mistaken belief that a trucker's urine still contains useable amounts of meth. You know where I'm going with this, right? Yep, it's true: desperate meth addicts have been known to scavenge the shoulders of America's highway, looking for discarded bottles of trucker urine which they can then drink.
And in a larger sense, the final is that our commercial systems are set up such that the people who deliver our goods cannot take reasonable bathroom breaks. However, one would hope that truckers who have to resort to peeing in bottles would at least have the courtesy to hang onto them until the next rest stop, and drop them in the trash.