Fly by night construction companies and handy man type businesses probably run by Mexican speaking people choose to drive down a desolate street at night and unload trash from the work site on the side of the road. It is a much cheaper alternative than driving way out to the only land fill in town and paying to dump the trash.
Vagrants and Homeless people live in the open in desolated swamp areas or under the shelter of Interstates. All their trash incidental to their living area piles up because there is no trash collection for homeless encampments.
Truck drivers who are paid on miles driven instead of hours worked make the most use of their time by eating in their trucks and when done, they toss the junk food trash out the window. Their thinking is, the roadside is already full of trash so why would anyone care if they added another bag of garbage to it. They have a valid point.
Adolescent misfits, construction crooks, and overworked truckers are giving Mobilians a real trashy Road Show.