Connectors are a type of link used to join two separate links. It is best practice to minimize the length of connectors whenever feasible (length through an intersection is the only exception). Connectors are intended to join links, not to serve as analysis segments where vehicles traverse long distances. Connectors are recommended to be used only where needed

Nodes are intersections of links and are used to determine intersection performance. It is recommended to establish a node-numbering scheme to facilitate error-checking and the aggregation of performance statistics for groups of links related to a specific facility or facility type. Nodes are drawn to capture all movements at the intersection by including all relevant links.

Conflict areas dictate how vehicles interact with each other between two links. Conflict areas affect vehicle movements on overlapping links or connectors by defining locations where vehicle movements conflict and determining which vehicle has priority. A conflict area can be used to code a do not block intersection area or a densely spaced urban area with considerable pedestrian interaction.

Like conflict areas, priority rules dictate how vehicles interact with each other between two links. It is recommended that priority rules only be used when conflict areas cannot reasonably replicate the desired interaction. They are also helpful in coding congested urban environments where it is important to have vehicles not block the intersections or approaches.

A desired speed decision (DSD) is a location on a link that, when crossed, will modify the desired speed of a vehicle. A vehicle does not accelerate or decelerate prior to encountering a DSD in anticipation of changing its desired speed. Rather, the DSD permanently updates the desired speed of a vehicle until the vehicle leaves the network or crosses a different DSD. Vissim provides a set of default desired speed distributions. New speed distributions can be created using field data. DSDs can be set for specific vehicle classes.

RSA are zones with a reduced speed. These can be used to temporarily slow the speed of vehicles traversing sharp turns on ramps or turning movements. A vehicle approaching a RSA decelerates in anticipation of it to reach its temporarily reduced desired speed. The RSA assigns a temporary desired speed to the vehicle, after which the desired speed of the vehicle reverts to the original desired speed set by the last DSD or the global network speed. A RSA only affects vehicles with a desired speed greater than the temporary speed assigned by it. If the desired speed is less than the RSA speed, the vehicle ignores it and continues to operate at the desired speed. RSA can be set for specific vehicle classes.

Ring barrier controllers (RBC) are used to create signal groups. The *.RBC file contains all the standard parameters of a signal controller with some advanced options. It is best practice to import an *.RBC signal file directly from Synchro as a baseline. It is recommended to check the signal timing in the Vissim RBC file against Synchro as values are sometimes not imported correctly. Save the *.RBC file in the same folder as the Vissim *.INPX file for Vissim to read it during model development and simulation.

Signal heads are typically placed at the same location as stop bars in the field. Modelers then assign signal heads to an *.RBC file. Assign all signal head a signal controller and phase. Signal heads at the same intersection can have the same signal controller number. Signal heads for the same movement can have the same phase number.

Detectors are used to detect vehicles and activate actuated traffic signals. The detectors are typically the same length and location as the detector in the field. Presence detection zone lengths are typically coded as 30 – 90 ft from the stop bar or from the signal head in Vissim. Advance detection zones should be placed 400 to 600 ft from the stop bar and should not be more than 50 ft in length. The detector is assigned to the same signal controller as the signal with the same port number as the phase that it activates. For detectors that control pedestrian signals, it is best practice to overlap the detectors with the pedestrian signal heads to make sure that relatively small pedestrians activate the detector.

Stop signs are placed at the same location as stop bars in the field. Dwell time distributions may be assigned to dictate how long a vehicle waits at a stop sign. Stop signs can be accompanied by priority rules and/or conflict areas to control multi-stop movements. RTOR movements are coded by placing stop signs on the right-turn connector and assigning the stop sign to the intersection’s signal group.