From memory (I took the pics) that one is an Isetta....which has always been my favourite.
There were also bubble cars from (yes ) BMW and Messerschmitt.
Lots in the late fifties/early sixties when I was a kid. Only motorbike licence needed.
I do remember them. And then how they went out of favour as people realised how dangerous they were. Only the Reliant Robin seemed to survive for a while...
The meschersmitt is such a strange looking vehicle..