I ride a pushbike so I see a lot of stuff on the road. Most valuable was a machine part worth 2 grand. I tried hard to give it back, in the end, I just threw it in the recycling bin. I spose I should have sold it on ebay. Ive found plenty of wallets, credit cards, ID cards, most I conclude were stolen, rifled through and thrown from cars. Down here 10k either side of a town is where things get lost from cars. Lots falls off roofs after this distance, purses, more wallets, anything that was left on the roof it seems. I once chased a lady who had her purse on her roof as she was driving from a car park, she thought I was trying to attack her lol.
Most common items not trash are U bolts, lead weights from tyres (great for fishermen) I see a hundred of them a day. Padlocks without keys are common. Then theres the gumboots, jackets and work bags that have fallen from utes. I find a lot of screw drivers and small spanners too, most likely from roofs as well. The odd phone from same place and plenty of work docket books. Tradies always leave things on roofs of cars, to lose the docket book is not fun for the people in the office I have found lol.
ZI rode around Austria for a month, I can honestly say the only piece of roadside rubbish I found was a full 1/2 litre beer can that went down a treat. Cleanest country Ive ever been to Austria, just a beautiful place. Didnt even see a train ticket on the ground.
Oh I have found a few wallets in gutters, I conclude fallen from passengers getting out of the car.