headway

 null == leader ? new DoubleScalar.Rel<LengthUnit>(Double.MAX_VALUE, LengthUnit.METER) : DoubleScalar.minus(
                leader.positionOfRear(thisEvaluationTime).getLongitudinalPosition(),
                follower.positionOfFront(thisEvaluationTime).getLongitudinalPosition()).immutable();

==============================================================================================================================

LaneChangeModelTest

/**
 * Local Node class.
 * <p>
 * Copyright (c) 2013-2014 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
 * BSD-style license. See <a href="http://opentrafficsim.org/node/13">OpenTrafficSim License</a>.
 * <p>
 * @version 14 nov. 2014 <br>
 * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
 */
class Node extends AbstractNode<String, Coordinate>
{
    /** */
    private static final long serialVersionUID = 1L;

    /**
     * @param id id
     * @param coordinate coordinate
     */
    public Node(final String id, final Coordinate coordinate)
    {
        super(id, coordinate);
    }

    /** {@inheritDoc} */
    @Override
    public final DirectedPoint getLocation() throws RemoteException
    {
        return new DirectedPoint(getPoint().x, getPoint().y, 0.0);
    }

    /** {@inheritDoc} */
    @Override
    public final Bounds getBounds() throws RemoteException
    {
        return new BoundingBox(0.1, 0.1, 0.0);
    }
}

/**
 * Local Link class.
 * <p>
 * Copyright (c) 2013-2014 Delft University of Technology, PO Box 5, 2600 AA, Delft, the Netherlands. All rights reserved. <br>
 * BSD-style license. See <a href="http://opentrafficsim.org/node/13">OpenTrafficSim License</a>.
 * <p>
 * @version 14 nov. 2014 <br>
 * @author <a href="http://www.tudelft.nl/pknoppers">Peter Knoppers</a>
 */
class Link extends CrossSectionLink<String, Node> implements LocatableInterface
{
    /** */
    private static final long serialVersionUID = 20140921L;

    /** speed. */
    private double speed;

    /**
     * @param id the id of the link (String).
     * @param nodeA the start node of the link.
     * @param nodeB the end node of the link.
     * @param length the length of the link with a unit.
     */
    public Link(final String id, final Node nodeA, final Node nodeB, final DoubleScalar.Rel<LengthUnit> length)
    {
        super(id, nodeA, nodeB, length);
    }

    /**
     * @return speed
     */
    public final double getSpeed()
    {
        return this.speed;
    }

    /**
     * @param speed set speed
     */
    public final void setSpeed(final double speed)
    {
        this.speed = speed;
    }