Overview

This Function shall be capable of providing the following facilities:

(1) The ability to provide the management of Vehicle speed and headway settings within the inter-urban road network.
(2) The ability to receive commands to implement legal speed settings, plus both suggested speed and headway settings from either the functionality providing the Road Network Operator interface, or the inter-urban traffic management functionality, or as part of an incident, demand management, or environmental strategy.
(3) The ability to ensure that requests from the Road Network Operator take priority and override those from the inter-urban traffic control functionality, but not override those that are part of an incident, demand management, or environmental strategy.
(4) The ability to send speed and headway settings to the inter-urban functionality that is responsible for the output of messages to Drivers, both at the roadside and in the Vehicle, as well as to other functionality from which it can be sent to other parts of the system and to the Broadcaster.
(5) The ability to send legal speed settings to the digital map data provider entity in case it needs to be used in future digital map updates.

Functional Requirements

(a) continuously monitor for receipt of the input data flows
(b) when the inter-urban road legal speeds data flow is received in (a) store its contents locally for future use
(c) as a result of (b) send the new inter-urban speed limits in the inter-urban legal speed limits data flow to the Provide Support for Host Vehicle Systems functionality
(d) when either the inter-urban speed and headway settings or the operator inter-urban speed override data flows are received in (a) implement the speed that they contain by sending the new speed limit in the inter-urban speed limit changes and updated inter-urban speed limits data flows
(e) in (d) the speed limit in the operator inter-urban speed override shall take precedence over the value in the inter-urban speed setting data flow, except where this is provided as part of an incident, demand or environmental management strategy
(f) as a result of (d) and (e) also send the new speed limit and headway to the Provide Support for Host Vehicle Systems functionality in the inter-urban suggested speeds and headways data flow and to the Output Lane & Speed Commands to Inter-urban Roads function in the inter-urban speed l&s commands data flow.

Diagrams

Parent Higher Level Function

• 3.1.2.13 Manage Inter-urban Traffic Strategies

Input logical dataflows

• mt_inter-urban_road_legal_speeds
• mt_inter-urban_speed_and_headway_settings
• mt_operator_inter-urban_speed_override

Output logical dataflows

• mt.pshvs_inter-urban_legal_speed_limits
• mt.pshvs_inter-urban_suggested_speeds_and_headways
• mt_inter-urban_speed_l&s_commands
• mt_inter-urban_speed_limit_changes
• mt_updated_inter-urban_speed_limits

User needs