Carriageways

Owned by Isabelle Avery (Unlicensed)
Last updated: Jul 10, 2023 by Charlotte Dakin-Norris
11 min read

Introduction

This section covers Carriageways; specifically their shape and setting configuration.

The carriageway functions as a virtual replica of the monitored highway. It is necessary to have a virtual carriageway in order to accurately detect, analyse and report incidents observed by the radar. The virtual carriageway creates parameters around the actual detection area. The ClearWay™ program cannot function without at least one carriageway.

Contents

Creating a Carriageway

This process is discussed in part of the Quick Setup Guide: .

Editing a Carriageway

As usual when configuring an Entity, go to the the Config tab, select the desired entity - in this case a carriageway - then select Edit to go into the edit mode. However, unlike some of the other shape, space and area related entities;, carriageways have certain specific configuration processes.

Manual Adjustment

To move the entire carriageway: Ctrl+Click+Drag when the🕂move icon appears.

For more detailed adjustments, examine the multiple circular icons of differing colours now visible on the carriageway. These points have a number of different functions.

The different functions of the points can be discerned by their colour:

  • Section Points: Pink.

  • Lane Points: Yellow.

  • Nodal Points: Green and blue.

  • Virtual Area Points: Red.

To isolate specific points to make them easier to move, the Point Filter box has a drop-down of options:

Show All: All points visible and available for configuration.

Sections: Section points visible and available for configuration.

Lanes: Lane points visible and available for configuration. 

Nodes: Nodal points visible and available for configuration.

Virtual Area: VA points are always visible and available for configuration, despite any of the above being selected. However, this option leaves solely VA points visible. 

To move individual points: Click+Drag over the coloured icons. However, certain movements are constrained:

Section points: These can only move up and down the carriageway.

Lane points: These can only move from side to side of a carriageway, along a node.

Node points: These can only move as far as the opposing side of the carriageway. The corresponding VA point moves with a node point, but the opposing node point remains in position - to move one node point just stretches a node.

To move the entire node (both nodal points), select Ctrl+Shift+Click+Drag over the blue node point.

VA points: These cannot move inside a carriageway, so a virtual (detection) area is always maintained inside the carriageway and the virtual area is intended to extend the track area outside the main carriageway.

Video

The following video shows how to edit the points in a carriageway:

Adding and Removing Lanes

To Add a Lane

  1. When a Carriageway is selected, the Configuration Panel displays the Carriageway Settings.

  2. Select Edit to enter the edit mode.

  3. To add a lane, select the Add button:

     

  4. A new lane tab will appear. Name the lane to label the lane tab and on the PPI.

  5. Stipulate Reverse Direction to create a counter-flow traffic lane. 

  6. Select Save.

Video

This short video shows how to add a lane:

To Remove a Lane

  1. When a Carriageway is selected, the Configuration Panel displays the Carriageway Settings.

  2. Select Edit to enter the edit mode.

  3. In the Lanes section, select the tab of the unwanted Lane, then select the Delete button

  4. The lane will immediately be deleted.

  5. Select Save.

Video

This short video shows how to remove a lane:

Lane Settings

You can edit the properties of each carriageway lane:

User ID: Numeric identification.

Name: The lane label.

Reverse Direction: Select this to change direction of traffic flow per lane.

Adding and Removing Sections

To add a section

  1. Select the Carriageway, then select Edit to enter the edit mode.

  2. The editing points will now be visible. Section points are pink. Find a section point directly adjacent to where you want to add a section.

  3. Ctrl+Left Click on the section point. Another section point will appear to the right of the original point. Left Click+Drag this new section point to adjust the size of your new section.

  4. Select Save.

To remove a section

  1. Select the Carriageway, then select Edit to enter the edit mode.

  2. The editing points will now be visible. Section points are pink. Find the section point of the section you want to remove.

  3. Ctrl+Right Click on the Section Point. A new window will appear to confirm the deletion of the section. Select OK to continue.

  4. Select Save.

Video

Here is a video showing how to add and then remove a section:

Section Settings

You can edit the properties of each carriageway section:

Sections: Select the section to configure.

User ID: The numeric identification of the section.

Name: The section label.

Relay: The number of the relay.

Distance (m): Length of the section.

Colour: Select to fill sections with colour of your choice.

Queue Density Modifier (%): This value acts as a local (per section) multiplier of the queue density threshold value set as a global setting or as a per-carriageway setting. As such, a value of less than 100% means that the section will have a greater tendency to be flagged as queued, and a value of more than 100% means that the section will have a lesser tendency to be flagged as queued.

Selected Point

Index: The index of the selected point relative to other points on the carriageway (internal use only).

Point Type: The type of point you have selected:

Top Point (Cyan): The top edge of the carriageway node.

Bottom Point (Green): The opposite edge of the carriageway node.

Lane Line (Yellow): Each lane has a movable point with each node.

Section Point (Magenta): The section point - each section has a single movable point.

Virtual Area Top Point (Red): The top point of the outer virtual detection area.

Virtual Area Bottom Point (Red): The opposite point of the outer virtual detection area.

X/Y: The co-ordinates of the selected point (carriageway node) on the X/Y axis of the PPI Display, with the radar as origin. The position cursor control can be used to move the selected carriageway nodal points.

Latitude/Longitude: The latitude/longitude reference of the selected point (carriageway node).

Carriageway Configuration

The global settings and edits available for carriageways are explained here: and on a User by User basis here:.

Carriageway settings available in the Configuration Panel once you have enabled Configuration Mode and selected the carriageway:

Basic Settings

Carriageway ID: The carriageway's identification number.

Name: The name of the carriageway.

Drive Side: This indicates the side of the road that the traffic travels along. For example, in the U.K. traffic travels on the left hand side.

Reverse Direction: Select this to toggle between left-hand and right-hand drive.

Speed Limit: The Speed Limit enables us to calculate expected travel times when there is no traffic in the carriageway or section. This field is not editable here. For information on how to edit this field please refer to .

Origin Distance: This property sets how far away the start of the carriageway is from the highway's true origin.

We can calculate where a vehicle is along the whole of a highway, but to do that we need to know the distance from the origin of the highway to the start of the carriageway configured in ClearWay™. For example, many motorways originate from London; this is considered to be their origin. In Clearway™, however, the carriageway maybe configured to start in Reading. To know how far a vehicle on the carriageway was from the origin (e.g. London), then we would need to know the distance from London to the start of our carriageway in Reading, plus the distance of the vehicle along the carriageway.

Layer: The layer that the carriageway is placed on.

Hide: Select this to hide the carriageway (turn translucent).

Virtual Tracking Areas: Select to auto-create a tracking area based on the shape of this carriageway.

Virtual Debris Tracking Areas: Select to auto-create a debris tracking area based on the shape of this carriageway.

Groups Restrict Tracking: Select this option if you want the selected groups of radar to only track on this carriageway. This will prevent radars from tracking on other carriageways even if they have line of sight.

Default Channel Index: Each radar has two channels for tracking two directions of travel. Match this value to the appropriate radar channel. 

Radar Groups: Select active radar group for this carriageway.

Carriageway Settings

Use Defaults: Select this to use the Global Default Settings: . Otherwise you can apply your own carriageway specific options.

By default all carriageways will use the Global Carriageway Settings and therefore any change made in the global settings will automatically be applied to all carriageways. If you want to use custom settings for each carriageway then you can choose not to use the default in which case all the settings are duplicated and you can change them for this specific carriageway without impacting any of the others.

Show Section Labels: Select this for labels to appear on this carriageway's sections (by default green and numerical).

Enable Queue Logic: Select to enable queue recognition software for this carriageway. Once implemented, queues will be be flagged and display visually through an orange fill in the detection area. 

Maximum Speed for Queue: The maximum traffic speed for a queue to be recognised in this carriageway. Anything faster will not be defined as a queue.

Heavy Traffic Threshold: The speed at which traffic is considered heavy on this carriageway.

Slow Track Density for Queue (/100m): How many tracks, travelling slower than the maximum queue speed, over one hundred metres, are necessary to considered a section in queue in this carriageway. This calculation of traffic density, as well the average speed of the traffic measured against the maximum queue speed, combine to recognise and alert queues. 

Reset Count Down (s): The time necessary to pass, after the queue rule has been broken, without the queue rule being broken again for the queue alert to be lifted in this carriageway.

Queue Break Allowance: The value the rule break count must reach in order to implement the queue logic. In order to cause a break both maximum queue speed and track density must be satisfied.

Queue Break Count Increment: The step value the queue break count will increase by when the rules are broken.

Queue Break Decrement: The step value the queue break count will decrease by when the rules are not broken.

Enable Auto Queue: Select this is you wish to implement Auto Queue for this carriageway. The software extrapolates on existing queue data to estimate potential or unrecognised queues.

Auto Queue Detection Window: How many of this carriageway's sections within every window the Auto Queue studies e.g. 4.

Auto Queue Section Count: How many of this carriageway's sections have to be in an existing queue in order for the Auto Queue to assume the entire window is in queue e.g. 2.

Sensor Allocation Mode:

Nearest: Detects data from this carriageway's sections assigned to them by proximity (by default).

All in Range: Detect data from all this carriageway's sections within their range, sometimes resulting in overlap and double-data. 

Count All Sightings: Select this option if you require all sightings to be used for statistics calculation regardless of the sensor allocation setting. This setting does not apply to Traffic Analysis.

Default Parameters: The parameters by which this carriageway will detect traffic. A sample selection of detection parameters, including a (default) Default configuration, is available. You are able to configure your own under Tracking Parameters. The default tracking parameters available are:

Default - Default tracking parameters.

Debris - Debris / stopped vehicle detection parameters.

Partial - Tracking parameters used where you need to track existing targets but do not want to create new tracks.

Default Debris Parameters: The parameters by which this carriageway will detect debris. A sample selection of detection parameters, including a (default) Debris configuration, is available. You are able to configure your own under Tracking Parameters. The default debris detection parameters available are:

Default - Tracking parameters.

Debris - Default debris / stopped vehicle detection parameters.

Partial - Tracking parameters used where you need to track existing targets but do not want to create new tracks.

Although you can select debris detection parameters for tracking (Default Parameters) and vice versa this is not recommended.

Statistics

Statistics Update Interval (s): The period of time between this carriageway's data updates, denoting how often an update occurs.

Statistics Storage Interval (s): The period of time between this carriageway's section data being transferred to the database, denoting how often a data transfer occurs. The data transferred is an aggregate of all the data collected within the time period of the Statistics Storage Interval.

Statistics Stale Timeout (s): The period of time in which no data is recorded from a particular section in this carriageway before it is ignored and not reported.

Statistics Minimum Seen (hits): The minimum number of times a vehicle must be seen before it is considered for section statistics. This provides a useful confidence level for each track, so that only longer lived tracks are counted and used to calculate average speeds.

Rule Update Interval (s): How often the radar checks for rules being broken in this carriageway.

Quiescence Timer (s): The period of time this carriageway must be detected and recorded as empty before it is officially reported as empty. Please see Carriageway Empty below.

Queue Colour: The colour of the sections when in queue.

Carriageway Empty

When a carriageway is detected and reported as empty, (as a result of the settings of the Quiescence Timer being satisfied) the Empty flag will be shown in the Carriageway Stats for a selected section, as in the example below:

The Empty Carriageway status can also be queried via a Highways Log Query within Playback:

This will display results such as in the example below:

Carriageway Traffic Analysis

Please see Traffic Analysis Plugin for more information: .

Actions

Actions are specific operations that can be carried out in relation to a carriageway. There are four Actions that can be initiated when a carriageway is selected whilst in Configuration Mode.

Rules: Select to open the Rules window to configure the Rules for the selected carriageway. See for further details.

Profile: Select to open the Profile Editor window to configure the carriageway operating modes. See for further details. 

Export to Layer: Select to export the carriageway outline as a new area to the Situational Awareness layer. Although the SA layer is selected by default, this outline area can be edited after it has been created and the layer can be changed.

Create POIs: Select to open the Create or Import Points of Interest wizard. See for further details.

There are two Actions that can only be initiated by first selecting Edit, and then the required Action:

Auto Section: Select to divide the carriageway into sections. See for further details.

Adjust Virtual Area: Select to open the Adjust Virtual Area window, and change the size of the detection area offset. The offset is the net area distance between the virtual detection area and the carriageway perimeter, and will always be a positive value, as the virtual detection area is always marginally larger than the carriageway. This is to account for a number of discrepancies; e.g. a margin of carriageway potting error, or detection at junctions adjoining the carriageway etc.

Safety is everything.