Side effect of over burdnsome eco nazi rules. They overcharge for something that used to be cheap, hence some shops have resorted to illegal disposal.
A common trick is to rent a storage unit, fill it with tires and stop paying on it. The month’s rent that you get charged on leasing, is much cheaper than disposing the tires that fill the unit.
And that is EXACTLY why you find MOUNTAINS of dirt, rocks, junk, excavation debris, tree trunks and limbs, and household waste all over California roads. It'll sit there for several years until the authorities haul it away. Then it reappears magically overnight. Some spots are so bad that they are completely full and the illegal dumpers have to find other spots.
A few years back, I drove to the local dump in Milpitas, CA and it was a $100 fee just to enter! Didn't matter if you had to dispose of a single sheet of paper -- $100 to just get in.
At our place in North Idaho, there are zero fees for residents. It's got the best waste disposal, hazardous waste drop-off, and recycling operation I've ever seen. Highly organized, no fees, great staff. You can drop off garbage, yard waste, cut-up trees, plastics, batteries, cardboard...you name it. And, because it's free, there are no mountains of waste on the roadsides.