Signal Control

A signal controlled junction in an Aimsun model has one or more Control Plans attached to it, each with a set of signal priorities, timings, and actuation rules. A control plan for a junction can use simple fixed times, it can use transit priority, NEMA ring control, or it can be linked to an external controller such as Yunex UTC (with SCOOT) or SCATS. The effect of the Adaptive Control Controllers in the simulation is that signals change at the times, or in response to traffic conditions, as they do on the road.

In a scenario, different options can be selected to test the effect of different signal control parameters under the different demand, transit, and geometry configurations selected for that scenario. This is achieved by creating a Master Control Plan which holds a self consistent set of control plans for each of the signalized junctions and selecting the master control plan for the scenario.

In use, the modeler will create as many different control plans as required for each junction. A control plan can then be re-used in multiple master control plans. By re-using control plans in different master control plans, the individual junction plans need only be created once and, if edited, the changes are reflected in all the master plans and therefore all the scenarios that use that control plan.

The Control Plan Generator can create a control plan for a junction with signal timings appropriate for the observed turn times and traffic volumes.

Also, Detection Patterns are used to provide a fixed set of data at detection loops. They are used in developing signal control algorithms using reproducible data to provide consistent inputs to the algorithm in development (i.e independent of the current simulation).