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Introduction

This section explains Rules: their purpose, the default choices and configuration.

Overview

Rules form the core intelligence of the system, permitting automatic decisions to be made based upon observed behaviour in the field. One of the great strengths of the ClearWay™ application is its ability to assist the operator by making decisions in response to sensed target movements. As a result, a continual watch can be placed upon all areas of interest, with the operator being alerted (or other actions initiated) only when particular criteria are met. The key factor in enabling such intelligent automated behaviour is the use of rules.

Rules consist of basic conditions, such as: 

  • ‘If a target enters this area then sound an alarm’ 

OR

  • ‘If a target is moving faster than 4 meters per second then follow it with a camera’.

Within ClearWay™ you can also combine two or more rules to apply very specific controls to particular regions. In addition to a set of adjustable default rules, you can also create any number of new rules using logical operators and other properties to achieve almost any desired outcome.

On this page:

Carriageway Wizard Rules  

When Adding a Carriageway, the Carriageway Wizard offers the opportunity to create the carriageway complete with a selection of default rules (see Configure Rules). 

  1. The first page of the wizard requires the default rules to be selected if required: 
  2. The second page of the wizard allows each default rule to be individually configured. Rule conditions form the core of each rule. The automated decision to take or not take action is determined using the properties that are combined here, and later in the Configure Rules window. Determine the choice of properties through decided what behaviour to isolate and which rule will achieve this. 


Configure Rules

There are 6 default rules:

  1. Person Rule
  2. Slow Vehicle Rule
  3. Reversing Vehicle Rule
  4. Queue Rule
  5. Debris Rule
  6. Stopped Vehicle Rule

Each is configurable, and has the ability to be switched on and off, or deleted. To configure the rules:

  1. Under the Config tab, select the Carriageway in the Entity Tree.
  2. In the configuration panel, select the ☰ options button next to Actions. 
  3. Select Rules, and a Configure Rules window will appear.

Creating a Rule

To manually create a new rule without using the wizard:

  1. In the Configure Rules window, select New.
  2. Select Rule Type:
    1. Speed Rule
    2. Queue Rule
    3. Classification Rule (can be applied to any classification, but is predominantly used for identifying Persons)
    4. Reversing Rule
    5. Track Speed Rule

  3. Select Create Rule. The new rule is now configurable as above.

    Speed, Queue, Classification and Reversing Rules are Section Rules. This means that every half second, each section is examined for evidence of these rules being broken.

    A Track Speed Rule is a Track Rule. This means that each track is individually examined as to whether it breaks this rule.

    Speed Rules and Track Speed Rules are different. A Speed Rule checks multiple tracks over time against speed parameters; i.e. looking for traffic, whereas a Track Speed Rule checks individual tracks against speed parameters. For an individual track to trigger an alarm we must be satisfied that the track is real and the rule is definitely broken, so a high break count is set. Therefore, a Track Speed Rule is therefore more suited to a Stopped Vehicle Rule.

Common Rule Settings

  1. Name: create concise yet distinctive names for rules. In situations where numerous rules are listed, it will make it much easier to locate the required one.
  2. Description: the text entered here will become your primary method of identification for the rule within the list. It can be advantageous to include the name of the monitored area or rule exceptions within the rule description for easy identification.
  3. Enabled: select this to make the rule active, and deselect to deactivate the rule. This is a useful way to quickly deactivate rules that are not needed temporarily. Default: Enabled.
  4. Sub Type: optionally allows you to define a particular movement classification (that should cause an alarm state) for vehicles within the detection area(s) under surveillance.
  5. Required Travel (m): the distance required for the track to have travelled before the rule is applied. Default: 0 m.
  6. Required Travel Direction: the direction of the track you are looking for Required Travel. For example if you specify a Required Travel distance of 20m and Required Travel Direction of Reverse, then for this rule to be broken you must see a track travel the wrong way along a carriageway for 20m. Default: Any.
  7. Use Speed Filter: defines rules' parameters by specified speeds or speed ranges. Default: Enabled.
    1. Breaking Condition: determines the parameters of the speed filter for the rule, in conjunction with the Min./Max. Speed values. Default: Is Smaller Than.
    2. Min./Max. Speed: determines the minimum and/or maximum speed of travel that should be used as the threshold(s) for a breaking condition. Default: 0 mph.
  8. Use Direction Filtering: applies the rule to tracks travelling in only one direction. This is typically used for bi-directional singe carriageways. Default: Disabled.
    1. Direction Source: defines the lane from which to take your direction of travel.
    2. Direction Filter: a value in degrees that specifies the margin in error (+ and -) for direction. So tracks with a direction based on the source and within the margin of error will be considered the rule checking.
  9. Show Area in Alarm:  when selected, the area or section in which the rule has been broken will be highlighted within the site map. Default: Enabled.
  10. Property Name: defines the numeric property that will be monitored by the rule. In each case, the Property Value 1 entry (and in some cases Property Value 2) are where you enter the corresponding value(s) to be ruled against for the chosen property. Default: None - no specific numeric property is monitored.
  11. Severity: defines how a target should be marked when it breaks a rule. Such markings allow a target to be easily differentiated. Default: Unknown.
  12. Action: defines the action that should be taken when a rule is broken. Default: None.
    1. Options are:
      1. None: take no action.
      2. Follow: automatically move a suitable camera to the incident.
      3. Alarm: display an alarm notification and audible noise in response to an incident.
      4. Alarm and Follow: do both of the above.
  13. Alarm Description: determines the text that will be presented to the operator (and entered in the activity log) when the rule is broken and an alarm is raised. Note that you can use the follow place holders which will automatically be populated with the relevant data when the alarm is raised:
    1. {CARRIAGEWAY} : Will be replaced with the carriageway name where the incident has occurred.
    2. {CARRIAGEWAYID} : Will be replaced with the carriageway user Id where the incident has occurred.
    3. {SECTION} : Will be replaced with the section name where the incident has occurred.
    4. {SECTIONID} : Will be replaced with the section user Id where the incident has occurred.
    5. {LANE} : Will be replaced with the lane name where the incident has occurred.
    6. {LANEID} : Will be replaced with the lane user Id where the incident has occurred.
    7. {RULEID} : Will be replaced with the user Id of the rule which has generated the alarm.
    8. {CLASSIFICATION} : Will be replaced with the classification description of the track causing the alarm.
  14. Alarm Priority: allows you to optionally apply a ‘weighting’ to any rules that invoke an Alarm Action. Default: Lowest
  15. Audible Alarm: select this for the alarm to be audible if breaking the rule results an alarm action. Default: Disabled.

Advanced

  1. Advanced:
    1. Break Allowance (s): alters the number of times that the rule can be broken before the defined Action is triggered. The default value of 1 will trigger an alarm at the first instance. Default: 1s or 1 hit.
    2. Use Allowance Curve: this option works in conjunction with the Break Allowance. When this option is enabled, the break count is permitted to go down as well as up. The break count will be incremented when a target is breaking the rule and then decremented when it is not. Additionally, you can set the Allowance Increment and Allowance Decrement values so that you can weight the rate at which a target increases and decreases its break count. The alarm will only be activated once the Break Allowance value is reached. This option is useful in situations where you expect targets to momentarily break rules but not to continue doing so and so prevent false alarms. Default: Disabled.
    3. Allowance Increment (s): (used only when Use Allowance Curve is enabled) Defines the amount by which the break count should be incremented every time a target breaks the rule. Default: 1s or 1 hit.
    4. Allowance Decrement (s): (used only when Use Allowance Curve is enabled) Defines the amount by which the break count should be decremented every time a target ceases to break the rule. Default: 1s or 1 hit.
    5. Relay: defines the Id of the relay that should be activated when the rule is broken. Choose ‘0’ to disable. Default: 0.
    6. Trace Logging: outputs more information about what causes the rule to break. Mainly used for carriageways with more convoluted rules. Default: Disabled.
    7. Count Coasted Tracks: select this to count coasted tracks towards the break allowance. De-select for them to be ignored. Default: Enabled.
  2. Classification Filters:
    1. Classification: optionally dedicate the rule to objects of a particular type as differentiated during the tracking process. When set to Any, the track must be classified but can be any classification. To include every track regardless of classification you must set this to Any and also select Include Unclassified. Default: Any.
    2. Classification Probability (%): allows you to optionally define a confidence level which must be matched or exceeded for a given track (of the type selected within the Classification option discussed above) before it can be considered within the rule. The use of this option provides an opportunity to filter out potential nuisance alarms. The main probability value is created during the tracking and classification process and is displayed against each entry within the Tracks tab. When this option is set to zero, the requested Classification type will be accepted at any level of probability (as determined by the tracker), rendering this filter inactive. Default: 0%.
    3. Include Unclassified: select this to include unclassified tracks as rule targets alongside the Classification filter. Default: Enabled.
  3. Alarm Suppression by Nearby Queue: this option will suppress this rule and alarm if there is a nearby queue. Either on a different carriageway, the same carriageway or both. This option is useful to reduce false alarms in one carriageway when there  is  heavy or queuing traffic in the other.
    1. Queue Detection Distance (m): how far to check for queues. This is a straight line distance from the alarm location to the nearest queue. Default: 0 m.
    2. Queue Source Filter: this is the carriageway filter which specifies on which carriageway to look for queues. Default: Other Carriageways.

Testing a Rule

Rules must be available to be tested to ensure that the correct alarms will be triggered when a rule is broken. In the Configure Rules window, there is a function for this exact task.

  1. Select the rule you wish to test. Then, select Test. 
  2. The Rule Test window will appear. Choose the Section and Lane you wish the alarm to be tested in, then select OK.
  3. On returning to the PPI Display, the alarm notifications will be visible (and if enabled, audible.)

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