I recall taking my motorcycle test, about 1953, on a push bike, fitted with a Minimotor, which was a 50cc engine with a roller driving on the back tyre! The emergency stop was when the examiner stepped out into the road, about 20yds ahead of me.
Went on to ride a Dot 197, finishing with a Matchless 500 twin, before moving on to my first car, which was a 1930 Morris Minor chassis with a 2 seater ash/aluminium body, which I built myself. (Photo attached)
Those were the days, can't see that happening today.