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Changing the desired speed

You can change the desired speed (DesSpeed), using the following network objects:

• Reduced speed areas for a temporary change (Using reduced speed areas to modify desired speed).
• DesSpeedDecisions (desired speed decisions) for a permanent change, for example on motorways, for traffic signs which limit the speed, or at the entry and exit of a town. DesSpeedDecisions are placed at the position where the change is to begin. For multi-lane links, position a desired speed decision on each lane and define the attributes.

With desired speed decisions, a vehicle only reduces its speed once it has entered a desired speed decisions section. The vehicle is then assigned a new desired speed and changes its speed accordingly. This is when its desired acceleration is used.

When entering the network, each vehicle is assigned a fractile value for speed distribution. This value remains unchanged during the entire simulation time. If this value is 40 %, the vehicle is always assigned a 40 percentile of the desired speed distribution for desired speed decisions. If the fractile is 100 %, the vehicle is always assigned the highest distributed speed.