Vehicle Interaction Criteria from Time Series Measurements

Vehicle interaction criteria are derived as a function of flow rate for each lane of a two-lane one-way highway. The data used were obtained from time series measurements at the flow rates of 1,479, 2,311, and 3,505 vehicles per hour. The basic approach is to study the dependency between successive speeds introduced by the interaction process. This study has shown that the phase of traffic flow for which vehicle interaction occurs can be defined in terms of time headway. A statistical analysis is used to determine the time headways below which vehicle interaction occurs (at the 1 per cent significance level); the resulting values vary between 2.5 sec and 4.3 sec depending on lane number and traffic flow rate. Plots of mean absolute relative speeds versus time headway show the effect of vehicle interaction as a function of time headway.