Source: adapted from R. Tolley and B. Turton (1995), p. 63.
Different urban transport modes have different operational speeds and capacities. The car is obviously the least efficient urban transport mode in terms of capacity (between 1,000 and 3,000 persons per hour), but the fastest, most convenient, and flexible. Urban transit modes, such as the bus, light rail, and heavy rail (subway) are better fitted for mass urban transportation but at the expense of flexibility in terms of frequency of services and entry points in the transit system. There is thus a trade-off between speed, capacity, and flexibility. The higher the level of economic development, the more this tradeoff is to the advantage of the automobile.