Horizontal and vertical separation of public and private transport to improve the fluidity of urban traffic : papers presented at the 35th International UITP congress, Vienna, 1963.

The horizontal separation can be made by special lanes for bus or tram traffic in the streets. This separation started in 1956 and proved satisfactory. Vertical separation is the most radical and effective form is in different levels. For economic reasons underground tramways are preferable. A comparison between the two systems is made.