Plymouth Voyager 3
From Dodge Wiki
The Plymouth Voyager 3 was a minivan concept car revealed in 1989. Part of its aerodynamic design featured a glass roof. One thing that was unique about this car was that in a sense it was a mini Tractor-trailer; the cab separated from the back of the car and could be driven by itself. The rear wheels of the cab were hidden(notice on image) when it was all in one piece.