As I was thinking about a new road design, I found a number that had been patented. The idea of patenting a road may seem a little strange, but it has happened a number of times. In very few cases have the patented designs become widely used. Some references below:
Continuous flow intersection
Traffic intersection – Patent 3915580
Simultaneous left turn vehicular intersection – US Patent 5795095
Vehicle highway system having single-level uninterrupted traffic-flow intersection – US Patent 5897270
Traffic interchange – US Patent 5921701
Some additional prior art cited in patents above:
1173505
February 1916 – Hale
1515251 November 1924 -Graves
1543080 June 1925 – Graves
3107590
October 1963- Cedeno
3272097
September 1966 –
Gazis et al.
3394638
Burrell
3915580 October 1975 – Kaufman
4592673
June 1986 – Lee
4630961 December 1986 – Hellwig
5049000 September 1991 – Mier
David Levinson, Transportist 