Urban Traffic Speeds—II: Relation of the Parameters of Two Simpler Models to Size of the City and Time of Day

Using the data collected by the RRL in 1967 for eight English cities, average speeds on major roads have been calculated as a function of distance from the city center. Two rather simple types of function have been fitted to this empirical data, namely v = k · r^1/3 and v = 60 − a · e^−r/R, and the values of their parameters have been found to be related to the city size and to whether the observations were made in the peak or the off-peak periods. Data from other studies, in London and Göteborg (Sweden), are adduced to support the conclusions drawn.