Believe it or not, Texas had an even worse roadway litter problem a few decades ago than we do now.
This is what some typical roadways looked like back in the 1960s & 1970s
This was along RM 2222 as it winds down the hill to Bull Creek.
This from Texas Highways Magaine
The history of one of the most successful ad campaigns ever
A Smithsonian Magazine Article about the very famous anti-litter campaign.