UC 27: iTLC Traffic signal optimization - active road user (ARU)

Operation use case

Purpose

The purpose of this use case is to optimise the traffic flow of active road users (ARU) at a intelligent light-controlled intersection (iTLC). Service providers will try to predict the expected behaviour of active road users on an iTLC and send priority requests (SRM1) to the iTLC based on this. The optimisation algorithm of the ITS application that controls the iTLC control can then take the arrival of the active road user into account for the optimisation. The rules that iTLC follows when optimising the phase control are determined by the algorithm of the iTLC supplier and the priority level that the road authority assigns to the various road users.

Action

Active road users, who are anonymized, share their location with a service provider using an ARU application. When an active road user is on an iTLC topology, his/her positions are transmitted to the relevant iTLC via the interchange in the form of CAM messages. Profiling is used to determine the most likely connection that the ARU user will make across the intersection. If the profiling is sufficiently strong (2-3 times the same connection at a iTLC), the service provider sends an SRM1 message containing the ETA until the profiled connection ID. If there is no or insufficient profiling for an intersection, no SRM1 messages can be sent. The active road user will get a form of feedback, the indicator at the physical requestbutton will light , a few seconds before arival of the active roaduser.

We accept that, based on profiling, SRM1 messages with incorrect connection IDs will also be sent. Profiling the ARU user is an educated guess and will never provide 100% certainty about the user's behavior.

Agreements

• The service provider will not send SRM1 messages from users who are already at the crossroads when they open the app.
• Based on the wishes of the road authority, the iTLC will only take into account an ARU user who sends both CAM and SRM1 messages. Users who only send CAM are not included for optimization.
• For an active road user who needs to cross the intersection via two or more connections, an SRM1 message will only be sent for the first connection. For the next connection(s) no SRM1 will be sent as long as the previous crossing is not guaranteed.

User's point of view

In this use case, the road user will not receive any visual or auditory feedback about the status of the priority request (SRM1), only a signal in the ARU application indicating that the app is active. The operation of this use case can translate into a shorter waiting time at the signal groups in which the road user is located, but the road user will not be informed about this.

Data sources

Road users

The road user shares the following information with the service provider:

• Type ARU: pedestrian or cyclist
• GPS locations with minimum requirements:
  • 1Hz frequency
  • Speed
  • Heading
  • Moment

Service Providers

Service providers draw up profiling of active road users for each intersection with iTLC.

Service providers calculate the ETA of an active road user to the most likely connection according to the profiling (as input for SRM0 message).

iTLC

An intersection topology must be present in ETSI MAP format of each active iTLC. The MAP contains a true representation of the lanes and/or tracks of the intersection. This is according to the Dutch Profile 3.0.0.

Data Processing (PIP)

The PIP is not in this chain.

RUF

No RUF applies.

MI & Historical Archive

The following data streams run over the MI:

• CAM (Cooperative Awareness Message)

  • Location data ARU users are published on the interchange as soon as the active road user is at the intersection topology.
  • In accordance with the Dutch Profile CAM specifications D3046-5 / Version 3.0.0, available on crow

• SRM1

  • From the active road user is on the map topology and within 90m of the iTLC (average distance to ingress/egress/connection).
  • including ETA to profiled connection

• MAP

The following data streams are archived after conversion:

CAM and SRM1 messages contain location data that can be linked to individuals. These messages are not (for the time being) stored in the historical archive.

MAP messages do not contain any personal information and can be stored in the historical archive.