org.opentrafficsim.core.gtu.following

Class IDM

java.lang.Object

org.opentrafficsim.core.gtu.following.AbstractGTUFollowingModel

org.opentrafficsim.core.gtu.following.IDM

All Implemented Interfaces:

GTUFollowingModel

public class IDM
extends AbstractGTUFollowingModel

The Intelligent Driver Model by Treiber, Hennecke and Helbing.

Copyright (c) 2013-2014 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved.
BSD-style license. See OpenTrafficSim License.

Version:

19 nov. 2014

Author:

Peter Knoppers

Field Summary

Fields inherited from class org.opentrafficsim.core.gtu.following.AbstractGTUFollowingModel

TOODANGEROUS

Constructor Summary

Constructors

Constructor and Description
IDM() Construct a new IDM car following model with reasonable values (reasonable for passenger cars).
IDM(DoubleScalar.Abs<AccelerationUnit> a, DoubleScalar.Abs<AccelerationUnit> b, DoubleScalar.Rel<LengthUnit> s0, DoubleScalar.Rel<TimeUnit> tSafe, double delta) Construct a new IDM car following model.

Method Summary

Modifier and Type	Method and Description
DoubleScalar.Abs<AccelerationUnit>	computeAcceleration(DoubleScalar.Abs<SpeedUnit> followerSpeed, DoubleScalar.Abs<SpeedUnit> followerMaximumSpeed, DoubleScalar.Abs<SpeedUnit> leaderSpeed, DoubleScalar.Rel<LengthUnit> headway, DoubleScalar.Abs<SpeedUnit> speedLimit) Compute the acceleration that would be used to follow a leader. TODO We should probably add a be ready to stop before argument to prevent vehicles that cannot see their leader, or should slow down for a crossing from accelerating to unsafe speeds.
String	getLongName() Return complete textual information about this instantiation of this GTU following model.
String	getName() Return the name of this GTU following model.
DoubleScalar.Rel<TimeUnit>	getStepSize() Return the step size of this GTU following model.
DoubleScalar.Abs<AccelerationUnit>	maximumSafeDeceleration() Return the maximum safe deceleration for use in gap acceptance models.

Methods inherited from class org.opentrafficsim.core.gtu.following.AbstractGTUFollowingModel

computeAcceleration, computeAcceleration, computeAccelerationWithNoLeader, minimumHeadway

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

IDM

public IDM()

Construct a new IDM car following model with reasonable values (reasonable for passenger cars).

IDM

public IDM(DoubleScalar.Abs<AccelerationUnit> a,
           DoubleScalar.Abs<AccelerationUnit> b,
           DoubleScalar.Rel<LengthUnit> s0,
           DoubleScalar.Rel<TimeUnit> tSafe,
           double delta)

Construct a new IDM car following model.

Parameters:

a - DoubleScalar.Abs<AccelerationUnit>; the maximum acceleration of a stationary vehicle (normal value is 1 m/s/s)

b - DoubleScalar.Abs<AccelerationUnit>; the maximum deemed-safe deceleration (this is a positive value). Normal value is 1.5 m/s/s.

s0 - DoubleScalar.Rel<LengthUnit>; the minimum stationary headway (normal value is 2 m)

tSafe - DoubleScalar.Rel<TimeUnit>; the minimum time-headway (normal value is 1s)

delta - double; the speed limit adherence (1.0; mean free speed equals the speed limit; 1.1: mean free speed equals 110% of the speed limit; etc.)

Method Detail

computeAcceleration

public final DoubleScalar.Abs<AccelerationUnit> computeAcceleration(DoubleScalar.Abs<SpeedUnit> followerSpeed,
                                                                    DoubleScalar.Abs<SpeedUnit> followerMaximumSpeed,
                                                                    DoubleScalar.Abs<SpeedUnit> leaderSpeed,
                                                                    DoubleScalar.Rel<LengthUnit> headway,
                                                                    DoubleScalar.Abs<SpeedUnit> speedLimit)

Compute the acceleration that would be used to follow a leader.
TODO We should probably add a be ready to stop before argument to prevent vehicles that cannot see their leader, or should slow down for a crossing from accelerating to unsafe speeds.

Parameters:

followerSpeed - DoubleScalar.Abs<SpeedUnit>; the speed of the follower at the current time

followerMaximumSpeed - DoubleScalar.Abs<SpeedUnit>; the maximum speed that the follower is capable of driving at

leaderSpeed - DoubleScalar.Abs<SpeedUnit>; the speed of the follower at the current time

headway - DoubleScalar.Rel<LengthUnit>; the net headway (distance between the front of the follower to the rear of the leader) at the current time

speedLimit - DoubleScalar.Abs<SpeedUnit>; the local speed limit

Returns:

DoubleScalar.Abs<AccelerationUnit>; the acceleration (or, if negative, deceleration) resulting from application of the GTU following model

getStepSize

public final DoubleScalar.Rel<TimeUnit> getStepSize()

Return the step size of this GTU following model.

Returns:

DoubleScalar.Rel<TimeUnit>; the step size of the GTU following model

maximumSafeDeceleration

public final DoubleScalar.Abs<AccelerationUnit> maximumSafeDeceleration()

Return the maximum safe deceleration for use in gap acceptance models. This is the deceleration that may be enforced upon a new follower due to entering a road or changing into an adjacent lane. The result shall be a positive value. In most car following models this value is named b.

Returns:

DoubleScalar.Abs<AccelerationUnit>; must be a positive value!

getName

public final String getName()

Return the name of this GTU following model.

Returns:

String; just the name of the GTU following model

getLongName

public final String getLongName()

Return complete textual information about this instantiation of this GTU following model.

Returns:

String; the name and parameter values of the GTU following model