Vehicle Movement Logic

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This section provides an overview of the logic/models employed to control the movement of vehicles within SwashSim.

The longitudinal (forward) motion of a vehicle (acceleration, velocity) is a function of the following factors:


 * proximity to a traffic control point (e.g., stop bar for a signalized intersection)
 * proximity to a downstream queue of traffic
 * proximity to a lead vehicle
 * actual speed relative to desired speed
 * proximity to change in change in free-flow speed for destination link

Acceleration Mode The above factors, which might apply individually or in combination, are used to assign an 'Acceleration Mode' to a vehicle. This Acceleration Mode is then used to assign a preset acceleration value or calculate one based on applicable factors and their current status. Acceleration Mode classifications assigned in SwashSim are:


 * CarFollow
 * UnimpededNormal
 * StoppingForQueue
 * StoppingForControl
 * Stopped
 * DownstreamLinkSpeedChange
 * SlowingForDowngrade
 * MaxAccel
 * MaxDecel
 * DesiredAccel
 * DesiredDecel

These classifications are discussed in more detail here.

Leader/Follower Status Desired Speed Maximum Acceleration Car Following Lane Changing Two-Lane Highway Passing