Vissim

VISSIM is a microscopic traffic flow simulation software developed by PTV Group. It models the movement of individual vehicles and pedestrians in road networks, enabling analysis of traffic operations, urban planning, and transportation projects.

The software uses a microscopic approach, employing car-following and lane-changing models, gap-acceptance, and weaving logic to reproduce interactions on streets, highways, and interchanges. It supports multimodal networks, including cars, buses, trams, bicycles, and pedestrians, and offers detailed simulation of signalized intersections, roundabouts, and priority rules. An integrated pedestrian model (VISWALK) allows simultaneous simulation of foot traffic.

VISSIM provides tools for calibration and validation, scenario management, and statistical outputs such as travel times, delays, queue lengths, and level of service. It also includes animation and visualization for network inspection. Data inputs can come from GIS, CAD, or existing network plans, and it interoperates with other PTV products such as VISUM for demand modeling and traffic assignment, enabling end-to-end planning from network design to operations.

Applications include corridor studies, intersection optimization, ITS and signal timing analyses, transit operations, and pedestrian facility planning. It is widely used by traffic engineers, city planners, and transportation agencies for evaluating capacity, throughput, safety improvements, and the effects of new mobility concepts or policies.

Developed by PTV Group, VISSIM has been available since the 1990s and is distributed as a commercial desktop application for Windows, with licenses and optional add-ons for extended functionality.