This is a mystery that i would like to solve, so if you have an answer for me please post it.
I lived in many placed around Europe but UK is the only place i see shoes, usually mens on the side of the roads and not the pair but just one.
This appears a lot and mainly on the busiest highways.
I have some theories, some strange theories about why this happens.
Since i see some news about road rage, maybe someone just tries to hit the other driver with the shoe. I have seen worth things in the road so maybe it is possible. So how that works? You get home and your wife asks you where is your other shoe and you just say that you wanted to help the other driver from falling asleep on the road hitting him in the head with the shoe, that is possible, right?
Maybe some cinderella was running from the cup cake party and left the shoe behind while running for not paying, i have no idea, but that i see a lot of shoes on the road next to the side walk and i do not know why.
Maybe is just a case of littering but why not the pair, why only one shoe?
If you know or think you know just send me your theory.