In November 1998, the Motorway Company "Autostrada Brescia Verona Vicenze Padova" decided to perform an evaluation on a limited scale for a system of central management and image processing (AID) on a 33 km stretch between Brescia & Verona of the highways A4 - A31 in Italy.

They selected Project Automation, a major traffic system integrator in Italy, closely co-operating with Traficon nv to co-ordinate this project.

In the survey, 12 fixed B/W cameras are involved, unevenly distributed over 6 postings on the road stretch. The average height is 15 metres. The length of the field of view is 400 metres (or more). The video signal is transmitted to the traffic control centre where it is processed by the detection equipment.

The AID system (Automatic Incident Detection) uses 2 Video Image Processing units (VIP41-VIP22) in parallel per camera.

The VIP22 uses a proprietary algorithm to measure the mean flow speed over the detection lines. Based on this measurements, alarms are produced for following actions :

• wrong way drivers: When a vehicle drives in the wrong direction an alarm is triggered within seconds.
• speed drop: When speed drops under normal traffic conditions, an alarm is triggered.
• queue formation: The system derives 4 levels of service (types of traffic ) from the traffic flow data.

The VIP41 uses the difference between the dynamic background and the current image to detect following action :

• stopped vehicles outdoors: on the highway and hard shoulder

A management system, provided by Project Automation handles the presentation of the alarms to operators at the traffic control centre.

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