Have you ever parked your car in a tight space and wish you could open / close its doors without having to damage cars on either side? If you have a car with vertical sliding doors, like the BMW Z1, you don’t have to worry about that. This video shows how BMW Z1’s sliding doors work.
This two-seat car was produced from March 1989 to June 1991. It was designed by Harm Lagaay. As you can see, the doors drop down into the door sills, making it easier to get in or out in tight spaces. More information is available here.