Basic technology of the automobile is now stable, but there are innovations in its "fitting'' in urban environment and its improved relationship with pedestrians and human activities in general. Technology of transit systems has had many innovations in the last 2-3 decades. There has been a general trend to provide partially or fully separated rights-of-way for transit. Buses and trolleybuses have been given special lanes or roadways in many cities. Separation of rail vehicles from other traffic has led to creation of light rail transit, a new mode that provides much better service than streetcars, trolleybuses and buses, but requires significantly lower investment than metros. Because of the great diversity of services it can offer, light rail transit is now being built in many cities around the world. Metro (rapid transit) systems have been built intensively in the last 30 years: their number increased from 17 in 1950 to over 60 today. There.are now attempts to develop small-scale automated metro systems, on rails or rubber tires, which require lower investments than metros and thus enable also medium size cities to upgrade their transit services.