Many municipalities are claiming a problem with what they call, euphemistically, "trucker bombs." No, it's not a terrorist threat, merely kind of gross. "Trucker bombs" are milk jugs full of pee, tossed to the side of the road so that the truck doesn't have to stop.
Now the easiest solution to this would be to collect them, empty them into a toilet, and flush. Of course, few people want to do this without at least a pair of disposable latex gloves and a nine hour shower afterwards to remove the dirty feeling. So the communities would like to identify the trucker responsible and punish him (truckers doing this are almost always male, guess why?) so that he doesn't do it again.
Two things are against DNA testing here. First, the jugs are not discovered for a while, and DNA tends to deteriorate when left outside a human body. Secondly, urine does not contain DNA, unless it brings with it epithelial cells, and the DNA is entirely confined to those cells. Truckers are unlikely to pee out these cells, as this only happens with people who have certain urological diseases. So chemical tests won't discover the identity of the culprit unless picked up immediately, while still warm. Ick.
If you combined my previous idea of uibiquitous internet, and motion-activated cameras, you could have it snap pictures of the vehicles of everyone who throws something out their window, but that wouldn't stop it immediately. What to do about these nasty jugs?
I propose robotic collection. Every few days, the robot is sent out to the highway, and picks up all white or yellow objects and puts them in a bin that it carries on its back.
And while it could be flushed, there's a better thing that could be done: Urine is rich in nitrogen, and would make an excellent fertilizer if watered down. So a field of crops could be watered from beneath with pipes fed from a water tank, which has a trucker bomb emptied into it once per emptying. A typical farm would consume 147 trucker bombs per day. Plants are thirsty.
147 trucker bombs tends to be the entire production of the Halifax area.