Red Light Photo Enforcement & Crime Scene Investigation William Fisher Photo Safety Program

How Does Red Light Photo Enforcement Work? Sequence 1.In-road sensors or above ground radar detect a vehicle’s speed above a pre‐determined threshold 2.Main camera captures Scene A image (vehicle behind the stop bar with the traffic signal red phase visible) and Scene B image (vehicle in detection zone) 3.Simultaneously, plate camera captures close-up of license plate 4.Video camera captures 12- second clip of incident

Red Light Camera System Equipment Main Camera: captures Scene A and Scene B images of the vehicle Plate Camera: zoomed image of rear license plate Video Camera: video images of the scene Connected to the traffic signal controller and detection sensors. Only active during the red phase.

Crime Scene Investigation Tool Call up a “plate of interest” in citations issued file to see possibly relevant past behavior data.

5 Crime Scene Investigation Tool Request footage of a particular red light location at a specific time and date to investigate: Suspicious Activity Replay of Accident “Drivers” Viewpoint of Scene, e.g. Blind Spots, Sun Glare, Weather Conditions, etc. Can Pull Plates from Video

6 Crime Scene Investigation Tool Look for anomalies in data. Do several separate anomalies have a connection or what caused the anomaly? Were traffic counts higher or lower around a particular incident? Why? Could it have impacted the situation? Average Traffic Speeds. Do lower traffic speeds imply some unusual activity holding up traffic around an incident? Speeders (even where speeding is not enforced). Was the same vehicle speeding through several intersections and away from an incident?

Roadway Piezo

Roadway Loops

The intersections have two sets of loops per lane, set as close as practical to the intersection. A vehicle must move over both sensors to record speed and time the signal light has been red. According to the vendor, speed is accurate within 1 mph. The timing for activation can be set at any interval required. In the City of Phoenix we require a 1/10 of a second delay.

Typical Roadway Loops

Cutting In Loops

There are vendors that use video loops that are projected onto the roadway from the camera system. These systems are not as accurate for speed. The vendor can supply a scattergram that shows vehicles and speed through a location within a set period of time. Your program is only as good as your contract with your vendor. It is imperative, when implementing photo enforcement, to understand the vendor’s capabilities and track record with other departments.

Redflex Traffic Systems: N 23 rd Ave Phoenix AZ American Traffic Solutions, Inc E Gray Rd Scottsdale AZ Vendors

Officer William Fisher #3976 City of Phoenix Police Department Traffic Education Safety Unit Photo Enforcement