ClearWay™ Rules

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 Default Rules below).

The first page of the wizard requires the default rules to be selected if required:
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 whether to generate an alarm or not is determined using the properties entered here. For example in the slow and stopped vehicle rules you can specify the minimum and maximum speeds for the vehicles that would qualify for either being stopped or moving slowly.

Typically the default parameters will work in nearly all situations, so careful thought should be given when changing the rule parameters and we recommend that any rule variations are tested to ensure the results are as expected.

Configuring Default Rules

When a new carriageway is created, 6 rules are created by default for this carriageway. There are 6 default rules:

Each is configurable, and has the ability to be enabled / disabled or deleted. To configure the rules:

Enable the Config Function, then select the Carriageway in the Configuration Tree.
In the Configuration Panel, select the Actions button.
Select Rules, and a Configure Rules window will appear.

Creating a New Rule

To manually create a new rule without using the wizard:

In the Configure Rules window, select New.
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
Select Create Rule. The new rule is now configurable as above.

Configuring a New Rule

To configure a new rule, please refer to the documentation concerning each rule section:

Speed, Queue, Classification and Reversing Rules are Section Rules. This means that, by default, each section is examined every half second 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 is breaking the rule.

Speed Rules and Track Speed Rules are different. A Speed Rule checks multiple tracks in each section over time against speed parameters; i.e. looking for common behaviour in 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 more suited to a Stopped Vehicle Rule where we are looking for at the behaviour of individual tracks.

Testing a Rule

Rules can easily be tested to ensure that the correct alarms is triggered when a rule is broken. In the Configure Rules window, you can generate a test alarm from any of the existing rules.

Select the rule you wish to test. Then, select Test.
The Rule Test window will appear. Choose the Section and Lane you wish the alarm to be tested in, then select OK.
The alarm notifications will be visible (and if enabled, audible) and the relevant section will change colour to reflect the alarm severity, assuming this option was selected in the rule configuration.