Here’s a cool parallel parking system build in the 50’s by Cadillac. The system was never implemented “at large” but this doesn’t remove anything from it’s coolness. Basically, a series of hydraulic pumps and gears pushes the spare wheel out from the trunk and rotates the back of the car easing the parallel parking process.
The Cadillac project was developed by Brooks Walker from Walker Research in San Francisco, US. There was another prototype developed by same inventor where he modified a 1953 Packard Cavalier to achieve the same results.featured the Walker’s Packard Cavalier in one of their posts, and the present owner of the car got in touch with them confirming the parking system exists and it’s fully operational.
While there is not much information available on the net regarding this cool project, I was able to find this 1932 US patent attributed to Mr Walker where the entire mechanism is explained and charted. Another reference of the fifth wheel parking system was made by the Life magazine (November 17th, 1952 issue) which also shows some images of the actual mechanism.