Junction Geometry

From simple junctions, to signal-controlled nodes and roundabouts with public transport priority and pedestrian interaction or "magic roundabouts" – with PTV Vissim it is possible to model and study any node geometry and any type of priority and signalling.

Signal control

Traffic signals affect the traffic flow dominantly, especially in urban areas. With PTV Vissim, traffic engineers can model and optimise all types of signal control – whether fixed time, traffic-actuated or public transport priority schemes. The software provides interfaces to all common controller types such as Sitraffic Office, SCOOT and SCATS, as well as to PTV Visum and PTV Vistro, in order to simulate and fine tune optimised controls.

Signal groups and phase-based fixed time control

Externally created intergreen matrices and signal programs can be imported into PTV Vissim or entered and then optimised. In this way, traffic engineers can create fixed time signal control based on signal groups: thanks to the clear representation of the signal states in a graphical editor, any intergreen violations can be quickly detected and corrected.

In addition, stage-based fixed time signal control can be created with the add-on module Vissig. Stages and interstages can either be defined via a graphical editor or generated automatically.

Traffic-actuated signal control

The add-on module VAP (Vehicle Actuated Programming) allows you to simulate adaptive signal control in PTV Vissim – for single intersections, with different strategies for public transport priority up to complex control systems for subnetworks. During the simulation, VAP interprets the program instructions of the controller logic and generates appropriate switching commands for the traffic signals.

VisVAP (Visual VAP) provides more convenience when defining the controller logic. This tool allows traffic engineers to create the logic in an easy-to-understand flowchart, using a library of commands for access to signal groups, stages and detectors. The logic is translated into VAP code for the simulation. The user may then follow the control logic step-by-step during the simulation. Discrepancies can be easily detected and fixed.

Vehicle actuated signal control in PTV Vissim, control logic designed and implemented in VisVAP (flow chart based)

Non-signalised intersections

Non-signalised intersections, such as roundabouts, junctions with give way signs or yellow boxes, can also be simulated with PTV Vissim. The links and connectors concept allows the generation of a detailed geometry. Conflict areas and priority rules can be used to define main flows and make detailed, optionally vehicle class-specific settings at the junction. These include settings for the acceptance of gaps and headways and for the range of sight.

Multimodality

PTV Vissim provides traffic engineers with a high degree of flexibility, which allows them to make their models even more realistic – including specific signalling of lanes and vehicles. Multiple signal heads can be placed on the same lane and use different vehicle class-related settings, so cyclists and cars on that lane can receive different signals.

Simulation of signal control for road traffic, pedestrians and public transport.

Furthermore, traffic engineers can define the compliance rate for different modes of transport in PTV Vissim. In this way, it is possible to analyse how jumping a red light affects the other traffic and whether there will be a reduction in capacity.

The results of different studies or individual modelling steps can be visualised in PTV Vissim at the press of a button. This aids the traffic engineer in the evaluation of planned measures. The simulation tool also provides a realistic representation in 3D, which is a bonus for any presentation to a non-technical audience.