Package org.opentrafficsim.road.gtu.lane.perception.headway

Interface Headway

All Superinterfaces:
Comparable<Headway>, org.djutils.base.Identifiable, PerceivedObject, Serializable
All Known Subinterfaces:
HeadwayGtu, HeadwayLaneBasedObject
All Known Implementing Classes:
AbstractHeadway, AbstractHeadwayCopy, AbstractHeadwayGtu, AbstractHeadwayLaneBasedObject, CarFollowingUtil.CarFollowingHeadway, HeadwayBusStop, HeadwayConflict, HeadwayDistance, HeadwayGtuPerceived, HeadwayGtuReal, HeadwayGtuRealCopy, HeadwayGtuSimple, HeadwayGtuType, HeadwayObject, HeadwayStopLine, HeadwayTrafficLight
public interface Headway extends PerceivedObject, Comparable<Headway>
Interface for a reference to information about a (lane based) GTU and a headway. The Headway can store information about GTUs or objects ahead of the reference GTU, behind the reference GTU, or (partially) parallel to the reference GTU. In addition to the (perceived) headway, several other pieces of information can be stored, such as (perceived) speed, (perceived) acceleration, (perceived) turn indicators, and (perceived) braking lights.
Special care must be taken in curves when perceiving headway of a GTU or object on an adjacent lane.The question is whether we perceive the parallel or ahead/behind based on a line perpendicular to the front/back of the GTU (rectangular), or perpendicular to the center line of the lane (wedge-shaped in case of a curve). The difficulty of a wedge-shaped situation is that reciprocity might be violated: in case of a clothoid, for instance, it is not sure that the point on the center line when projected from lane 1 to lane 2 is the same as the projection from lane 2 to lane 1. The same holds for shapes with sharp bends. Therefore, algorithms implementing headway should only project the reference point of the reference GTU on the center line of the adjacent lane, and then calculate the forward position and backward position on the adjacent lane based on the reference point. Still, our human perception of what is parallel and what not, is not reflected by fractional positions.

Copyright (c) 2013-2024 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
BSD-style license. See OpenTrafficSim License.

Author:
Alexander Verbraeck, Peter Knoppers

  • Nested Class Summary

    Nested Classes
    Modifier and Type
    Interface
    Description
    static enum 
    Headway.ObjectType
    the object types that can be distinguished for headway.

  • Method Summary

    Modifier and Type
    Method
    Description
    default int
    compareTo(Headway headway)
    org.djunits.value.vdouble.scalar.Acceleration
    getAcceleration()
     
    org.djunits.value.vdouble.scalar.Length
    getDistance()
    Retrieve the strongly typed distance to the other object.
    String
    getId()
     
    org.djunits.value.vdouble.scalar.Length
    getLength()
     
    Headway.ObjectType
    getObjectType()
     
    org.djunits.value.vdouble.scalar.Length
    getOverlap()
    Return the (perceived) overlap with the other object.
    org.djunits.value.vdouble.scalar.Length
    getOverlapFront()
    Return the (perceived) front overlap to the other object.
    org.djunits.value.vdouble.scalar.Length
    getOverlapRear()
    Return the (perceived) rear overlap to the other object.
    org.djunits.value.vdouble.scalar.Speed
    getSpeed()
     
    boolean
    isAhead()
     
    boolean
    isBehind()
     
    boolean
    isParallel()
     

  • Method Details

    • getId

      String getId()
      Specified by:
      getId in interface org.djutils.base.Identifiable
      Returns:
      String; the id of the other object for comparison purposes, cannot be null.

    • getLength

      org.djunits.value.vdouble.scalar.Length getLength()
      Returns:
      Length; the length of the other object; can be null if unknown.

    • getSpeed

      org.djunits.value.vdouble.scalar.Speed getSpeed()
      Returns:
      Speed; the (perceived) speed of the other object; can be null if unknown.

    • getDistance

      org.djunits.value.vdouble.scalar.Length getDistance()
      Retrieve the strongly typed distance to the other object.
      Returns:
      Length; the distance to the object, return value null indicates that the other object is parallel to the reference object

    • getObjectType

      Headway.ObjectType getObjectType()
      Returns:
      Length; the (perceived) object Type, can be null if no object type unknown.

    • getAcceleration

      org.djunits.value.vdouble.scalar.Acceleration getAcceleration()
      Returns:
      Acceleration; acceleration the (perceived) acceleration of the other object; can be null if unknown.

    • getOverlapFront

      org.djunits.value.vdouble.scalar.Length getOverlapFront()
      Return the (perceived) front overlap to the other object. This value should be null if there is no overlap. In the figure for two GTUs below, it is distance c, positive for GTU1, negative for GTU2. 
       ----------
 |  GTU 1 |          ----->
 ----------
      ---------------
      |    GTU 2    |          ----->
      ---------------
 | a  | b |     c   |
      Returns:
      Length; the (perceived) front overlap to the other object or null if there is no overlap.

    • getOverlapRear

      org.djunits.value.vdouble.scalar.Length getOverlapRear()
      Return the (perceived) rear overlap to the other object. This value should be null if there is no overlap.In the figure below for two GTUs, it is distance a, positive for GTU1, negative for GTU2. 
       ----------
 |  GTU 1 |          ----->
 ----------
      ---------------
      |    GTU 2    |          ----->
      ---------------
 | a  | b |     c   |
      Returns:
      Length; the (perceived) rear overlap to the other object or null if there is no overlap.

    • getOverlap

      org.djunits.value.vdouble.scalar.Length getOverlap()
      Return the (perceived) overlap with the other object. This value should be null if there is no overlap. In the figure below for two GTUs, it is distance b, positive for GTU1 and GTU2. 
       ----------
 |  GTU 1 |          ----->
 ----------
      ---------------
      |    GTU 2    |          ----->
      ---------------
 | a  | b |     c   |
      Returns:
      Length, the (perceived) overlap with the other object or null if there is no overlap.

    • isAhead

      boolean isAhead()
      Returns:
      whether the other object is in front of the reference object.

    • isBehind

      boolean isBehind()
      Returns:
      whether the other object is behind the reference object.

    • isParallel

      boolean isParallel()
      Returns:
      whether the other object is parallel the reference object.

    • compareTo

      default int compareTo(Headway headway)
      Specified by:
      compareTo in interface Comparable<Headway>