Factors Affecting Travel Times on Urban Radial Routes.

This paper presents the results-of a study of peak period travel times and potential causal factors conducted over a one year period on five radial routes. It describes the hypotheses tested and the survey design adopted and then presents results for inter-vehicle variation in travel time within 250 15 minute periods and for inter-period variation based on 1018 moving observer runs. Moving observer results are found to depend on flow over the previous half hour, and a modified time series analysis used to demonstrate this is outlinzd. The contriuhtion of other explanatory variables is also presented.