Package org.opentrafficsim.road.gtu.generator

Class GeneratorPositions.LaneBias

  • Enclosing class:
    GeneratorPositions
    public static final class GeneratorPositions.LaneBias
extends Object
    Vehicle generation lateral bias. Includes a lane maximum, e.g. trucks only on 2 right-hand lanes.

    Copyright (c) 2013-2020 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
    BSD-style license. See OpenTrafficSim License.

    Version:
    $Revision$, $LastChangedDate$, by $Author$, initial version 22 dec. 2017
    Author:
    Alexander Verbraeck, Peter Knoppers, Wouter Schakel

    • Field Detail

      • WEAK_LEFT

        public static final GeneratorPositions.LaneBias WEAK_LEFT
        Weak left-hand bias, 2nd left lane contains 50% relative to left most lane, in free traffic.

      • LEFT

        public static final GeneratorPositions.LaneBias LEFT
        Left-hand bias, 2nd left lane contains 25% relative to left most lane, in free traffic.

      • STRONG_LEFT

        public static final GeneratorPositions.LaneBias STRONG_LEFT
        Strong left-hand bias, 2nd left lane contains 3.125% relative to left most lane, in free traffic.

      • WEAK_MIDDLE

        public static final GeneratorPositions.LaneBias WEAK_MIDDLE
        Weak middle bias, 2nd left lane contains 50% relative to left most lane, in free traffic.

      • MIDDLE

        public static final GeneratorPositions.LaneBias MIDDLE
        Middle bias, 2nd left lane contains 25% relative to left most lane, in free traffic.

      • STRONG_MIDDLE

        public static final GeneratorPositions.LaneBias STRONG_MIDDLE
        Strong middle bias, 2nd left lane contains 3.125% relative to left most lane, in free traffic.

      • WEAK_RIGHT

        public static final GeneratorPositions.LaneBias WEAK_RIGHT
        Weak right-hand bias, 2nd right lane contains 50% relative to right most lane, in free traffic.

      • RIGHT

        public static final GeneratorPositions.LaneBias RIGHT
        Right-hand bias, 2nd right lane contains 25% relative to right most lane, in free traffic.

      • STRONG_RIGHT

        public static final GeneratorPositions.LaneBias STRONG_RIGHT
        Strong right-hand bias, 2nd right lane contains 3.125% relative to right most lane, in free traffic.

    • Constructor Detail

      • LaneBias

        public LaneBias​(GeneratorPositions.RoadPosition roadPosition,
                double bias,
                double stickyLanes)
        Constructor.
        Parameters:
        roadPosition - RoadPosition; lateral position on the road (0 = right, 0.5 = middle, 1 = left)
        bias - double; bias extent, lower values create more spread traffic, 0.0 causes no lane preference
        stickyLanes - double; number of lanes to consider in either direction, including the preferred lane

    • Method Detail

      • bySpeed

        public static GeneratorPositions.LaneBias bySpeed​(Speed leftSpeed,
                                                  Speed rightSpeed)
        Returns a bias by speed with normal extent.
        Parameters:
        leftSpeed - Speed; desired speed for full left bias
        rightSpeed - Speed; desired speed for full right bias
        Returns:
        bias by speed with normal extent

      • bySpeed

        public static GeneratorPositions.LaneBias bySpeed​(double leftSpeedKm,
                                                  double rightSpeedKm)
        Returns a bias by speed with normal extent. Convenience km/h input.
        Parameters:
        leftSpeedKm - double; desired speed for full left bias
        rightSpeedKm - double; desired speed for full right bias
        Returns:
        bias by speed with normal extent

      • calculateWeight

        public double calculateWeight​(int laneNumFromRight,
                              int numberOfLanes,
                              int numberOfUnplacedGTUs,
                              Speed desiredSpeed)
        Returns a random draw weight for given lane. The weight is calculated as: 
         weight = { 0,                               d >= number of sticky lanes
          { 1 / ((d + 1)^bias * (m + 1)),    otherwise
 
 where,
      d:      lane deviation from lateral bias position
      bias:   bias extent
      m:      number of unplaced GTU's
        The formula makes sure that all lanes have equal weight for bias = 0, given an equal number of unplaced GTU's m. The bias can be seen to result in this: for each GTU on the 2nd lane, there are 2^(bias - 1) GTU's on the 1st lane. In numbers: 1 vs. 1 for bias = 0, 1 vs. 2 for bias = 1, 1 vs. 4 for bias = 2, 1 vs. 8 for bias = 3, etc.

        Division by m + 1 makes sure traffic distributes over the lanes in case of spillback, or otherwise too high demand on a particular lane. The weight for lanes with more unplaced GTU's simply reduces. This effect balances out with the bias, meaning that for a strong bias, GTU's are still likely to be generated on the biased lanes. Given a relatively strong bias of bias = 5, the weight for the 1st and 2nd lane becomes equal if the 2nd lane has no unplaced GTU's, while the 1st lane has 31 unplaced GTU's.

        Lane deviation d is calculated as d = abs(latBiasLane - laneNumFromRight). Here, latBiasLane = 1 + roadPosition*(numberOfLanes - 1), i.e. ranging from 1 to 4 on a 4-lane road. For lanes that are beyond the number of sticky lanes, the weight is always 0.

        Parameters:
        laneNumFromRight - int; number of lane counted from right to left
        numberOfLanes - int; total number of lanes
        numberOfUnplacedGTUs - int; number of GTU's in the generation queue
        desiredSpeed - Speed; desired speed, possibly used to determine the biased road position
        Returns:
        double; random draw weight for given lane

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object