This High-level Function shall provide the facilities needed control traffic using the urban road network. It shall be possible for the traffic to be controlled using indications that may be commands to stop and go, or messages asking that certain other actions are taken, e.g. divert to alternative route. Thus the output of the commands shall be possible through devices providing single or multiple indications, and/or text messages. The Function shall include facilities that enable priority to be given to selected road users both at individual points and on routes through the road network. The operation of output Functions shall be monitored and incorrect responses reported.<br/>