Evaluation interval duration needed to determine the travel times

The simulation of the traffic flow is used during the dynamic assignment to determine travel times in the network. The travel times are measured for every edge and every evaluation interval (Attributes for the trip chain file, matrices, path file and cost file).

In dynamic assignment, as opposed to static assignment process, traffic demand and infrastructure are not assumed to be constant over time. Therefore the traffic condition in the network and as a result the travel times will change during the assignment time period. Therefore to cover these changes the total simulation time is divided into smaller evaluation intervals in which travel times are observed separately. An evaluation interval also specifies the point in time after which the path selection of vehicles changes The appropriate duration of the evaluation interval depends on the dynamics of the traffic demand. Select a time period during which the traffic situation is expected to change significantly. In doing so, take the entire simulation period into account, including possible evaluation intervals.

Evaluation intervals of less than 15 minutes rarely make sense, as fluctuations of the measured values increase with shorter intervals. In many cases, evaluation intervals from 15 to 60 minutes are appropriate.

Especially when signal controls are used the evaluation interval must be significantly longer than the cycle times used.