PTV

In VISSIM, the movement of pedestrians is based on the Social Force Model. The basic idea is to model the elementary impetus for motion with forces analogously to Newtonian mechanics. From the social, psychological, and physical forces a total force results, which then sums up to the entirely physical parameter acceleration. The forces which influence a pedestrian’s motion are caused by his intention to reach his destination as well as by other pedestrians and obstacles.

Prof. Dr. Dirk Helbing from ETH Zurich acts as scientific advisor for PTV AG. For the use in VISSIM the Social Force Model was specially expanded by him. This simulation model was validated in a threefold way: firstly, macroscopic parameters were calculated and compared to empirical data, secondly it was assured that microscopic effects like lane formation in counterflow situations
and stripe formation in crossing flow situations are reproduced, and thirdly a realistic impression of resulting animations was in the focus.

For pragmatic reasons, the behaviour of pedestrians is often classified hierarchically into three levels

► On the strategic level (minutes to hours), a pedestrian plans his route. He generates a list of destinations.

► On the tactical level (seconds to minutes), the pedestrian decides on the route between the destinations, making a rough routing decision.

► On the operational level (milliseconds to seconds), the actual movement is performed. This includes evading opposing persons, moving through a dense crowd, or simply continuing the movement toward the destination.

Here, the Social Force Model controls the operational level and parts of the tactical level, whereas the strategic level is defined by the user input.

For further information please visit www.ptvag.com or www.ptvag.com/index.php to watch a pedestrian simulation.