Jugs of Pee appear to be a national epidemic, although reports continue to emanate chiefly from the West. The littering of highways with urine-filled plastic bottles is traditionally linked to weak bladdered long-haul rig drivers, despite official denials by trucker trade associations. Now authorities suspect a crossover into the general driving population, judging by the amount of bottles surprising road crews. Crews in southeastern Washington state reported over 1,000 bottles in a one month period for a 100 mile section of highway.
The bottles are predominantly plastic beverage containers from convenience stores -- milk, juice, etc. Capped and thrown from a moving vehicle, some retain their seal. In the summer heat, urine bottles build up pressure and when nudged by a clean-up crew may explode, or be spun into the air by lawnmower blades.
Urine-filled Bottles. Roadside America