Highway Carelessness Or Intentional Acts of Mischief

Those who know me, know that I used to bike a lot of miles and run in 10k races. Never came close to winning any, but got lots of exercise. Have given up on the running, but still walk many, many miles, and having grown bored of seeing the same sights along the paved "Silver Comet" trail, I have commenced walking along our many highways and biways, generally - because of the traffic - walking areas that have sidewalks. I constantly seek out new roads to walk. It disgusts me that people are so sloppy, inconsiderate and careless when it comes to littering. Many of our roadsides, which could be quite attractive because the county plants flowers and trees along most areas, resemble a landfill. During the past year, I have found two cellphones (one fully functional), several wrenches of various variety, three screwdrivers, 10 or 12 live bullets (yup, 380, 9mm & 40c) numerous empty shell casings, which could mean that someone is driving along and firing a gun out of their car window, (This thought makes me shudder) or just throwing the casings out of their car window. What concerns me the most is the thousands (yes, thousands) of nails, nail-screws, screws, bolts, nuts, (all sorts of hardware) that line the roads. These items are tire destroyers and could cause serious accidents. My inquisitive - police - mind causes me to wonder if all of this destructive debris is accidentally dropping out of contractors vehicles or, being intentionally scattered by tire dealers, or - God forbid - angry, hate-filled people. What is your take on this problem?
I would add, that I am a volunteer that assists my friend in cleaning up a one-mile section of South Cobb Parkway in Smyrna, and we have collected every sort of debris imaginable, including: baby diapers, condoms, crack containers, syringes, etc. Makes me wonder if our society has become so lazy, self-centered and corrupt, that very few people take pride in being clean and neat. Also wonder what the homes of the slobs doing all this littering look like...