Editing the driving behavior parameter Lateral behavior

By default, in Vissim a vehicle uses the entire width of the lane. You can define in the driving behavior and parameters-lateral behavior, whether the vehicles in a lane can drive on the left, on the right or in the middle without specifying a lateral orientation. If the lane is wide enough and the attributes in the section Default behavior when overtaking vehicles on the same lane or on adjacent lanes allow for overtaking on the same lane, overtaking maneuvers on a single lane are also possible. If the maximum deceleration prevents the overtaking vehicle from braking in time, it overtakes the other vehicle if possible, even if this is not allowed by the driving behavior parameters Consider next turn and Minimum lateral distance. Improper overtaking therefore takes precedence over a collision.

In addition, these settings are used when the option Observe adjacent lane(s) is selected.

1.  On the Base Data menu, click > Driving Behaviors.

The Driving Behaviors list opens. Some driving behavior parameter sets can be predefined.

You can edit all driving behavior parameters for lane change, lateral behavior and following behavior in the list or in tabs with the following steps.

Note: In lists, you can use the  Attribute selection icon to show and hide attribute values (Selecting attributes and subattributes for columns of a list).

By default, you can edit the list (Using lists).

2.  Right-click the entry of your choice.

3.  On the shortcut menu, click Edit.

The Driving Behavior window opens.

4.  Select the Lateral tab.

5.  Make the desired changes:

Element Description

Desired position at free flow

Desired position at free flow (DesLatPos): Lateral orientation of a vehicle within its lane while it is in free traffic flow.

If you change the traffic rules in the network settings, Vissim will change the attribute values Right to Left and Left to Right (Selecting network settings for vehicle behavior).

Observe adjacent lanes

ObsAdjLns: If this option is selected, vehicles account for the position and lateral orientation of other vehicles on adjacent lanes and keep the Minimum lateral distance. For this purpose, vehicles even adjust their lateral orientation on their own lane and swerve out of the way. The simulation also regards the actual positions of the back ends of vehicles, which change a lane to an adjacent lane or have already changed.

 If this option is not selected, vehicles on adjacent lanes are ignored even if they are wider than their lanes, except when they perform a lane change.

Note: Using this option can reduce the simulation speed significantly!

Diamond queuing

DiamQueu:  If this option is selected, queues take into account a realistic shape of the vehicles with vehicles positioned offset, such as bikes. Vehicles are internally represented not as a rectangle, but as a rhombus.

Consider next turn

ConsNextTurn: In case of non-lane-bound traffic enables a lateral behavior that accounts for another vehicle as follows:  If the option has been selected, a vehicle with this driving behavior does not pass another vehicle on the same lane if this could cause a collision at the next turning connector. To achieve this, attributes that enable passing on the same lane must be selected in the section Default behavior when overtaking vehicles on the same lane or on adjacent lanes and/or vehicle classes that may be overtaken must be selected in the section Exceptions for overtaking vehicles of the following vehicle classes.

Option Consider next turn also considers the attribute Desired Direction of the next connector of the route of the vehicle (Attributes of connectors). If, for example, left has been selected for this attribute, the vehicle only passes another vehicle on the right if that vehicle turns at the same connector at the latest.

The vehicle flashes when the following conditions are met:

  • the option Consider next turn is selected
  • the vehicle performs a lane change within the lane change distance
  • the attribute Left or Right of the connector is selected
  • the vehicle is driving

Note: The option Consider next turn has precedence over option Desired position at free flow.

Collision time gain

Minimum collision time gain (MinKCollTimeGain): Minimum value of the collision time gain for the next vehicle or signal head, which must be reached so that a change of the lateral position on the lane is worthwhile and will be performed. The collision time is calculated based on the desired speed of the vehicle. The default value for collision time gain is two seconds. Smaller values lead to a livelier lateral behavior, since vehicles also have to dodge sideways for minor improvements. Default 2.0 s

Minimum longitudinal speed

Minimum longitudinal speed for lateral movement (MinSpeedForLat): Minimum longitudinal speed which still allows for lateral movements. The default value of 1 km/h ensures that vehicles can also move laterally if they have almost come to a halt already.

Time between direction changes

Lateral direction change - minimum time (Lateral behavior) (LatDirChgMinTm): the default value 0.0 s defines the minimum simulation time which must pass between the start of a lateral movement in one direction and the start of a lateral movement in the reverse direction. The larger this value is, the lower the lateral movements of the vehicles. These lateral movements only take place if overtaking on the same lane is permitted. Lateral movement for a lane change is not affected by this attribute.

Default behavior when overtaking vehicles on the same lane or on adjacent lanes

This applies for all vehicle classes, with the exception of the vehicles classes listed under Exceptions for overtaking vehicles of the following vehicle classes.

  • Overtake on same lane: When modeling traffic that is not lane-bound, you can allow vehicles to overtake within a lane.

  • Left: Vehicles are allowed to overtake on a lane to the left
  • Right: Vehicles are allowed to overtake on a lane to the right
  • Minimum lateral distance: Minimum distance between vehicles when overtaking within the lane and keeping the distance to vehicles in the adjacent lanes.
  • Distance standing at 0 km/h (LatDistStandDef): lateral distance of the passing vehicle in meters. Default value: 0.2 m
  • Distance driving at 50 km/h (LatDistDrivDef): lateral distance of the passing vehicle in meters. Default value: 1.00 m

The minimum lateral distance is multiplied by the stochastic value z:

  • z, in the value range [0.5 to 1.5], is normally distributed around 1.0 by default, with a standard deviation of 0.15.
  • z is 1.0, if for the following behavior the attribute Use implicit stochastics is deactivated.
  • For speeds other than 0 km/h or 50 km/h, the minimum distance is interpolated linearly.

 If the option Observe adjacent lanes is not selected, vehicles on adjacent lanes are ignored even if they are wider than their lanes, except when they perform a lane change (Editing the driving behavior parameter Lane change behavior).

Exceptions for overtaking vehicles of the following vehicle classes

Behavior for specific vehicle classes that deviates from the default behavior when overtaking vehicles on the same lane or on adjacent lanes. When modeling traffic that is not lane-bound, you can select vehicle classes which may be overtaken within a lane by vehicles of this driving behavior set.

1.  Right-click in the list.

2.  On the shortcut menu, click Add.

A new row with default data is inserted.

3.  Make the desired changes:

  • VehClass: Vehicle class whose vehicles may be overtaken by vehicles of this driving behavior parameter set within the lane.
  • OvtL (Overtake left): Vehicles are allowed to overtake on the left lane
  • OvtR (Overtake right): Vehicles are allowed to overtake on the right lane
  • LatDistStand: Minimum distance at 0 km/h
  • LatDistDriv: Minimum distance at 50 km/h