Aug. 22: Calcutta police have started installing automatic number-plate recognition cameras capable of photographing vehicles violating traffic signals even at night.

Cameras with infrared sensors that see in the dark are being fixed above the stop lines at 10 intersections where the maximum volume of traffic and violations are reported.

The Park Street-JL Nehru Road crossing and the Minto Park intersection are among the first to get these cameras. Lalbazar has procured more than 40 cameras - the project would cost a few crores of rupees - in the first phase. The cameras being installed could be operational before Durga Puja next month, sources said.

Metro had reported on March 17 about the traffic police department putting automatic number-plate recognition cameras on the top of its wish list. The project was sanctioned shortly after.

At the Park Street-JL Nehru Road crossing, the police have installed two pairs of cameras - a pair each on the north and south-bound flanks of JL Nehru Road. To ensure proper illumination and better picture quality, two lights have been installed alongside the cameras.

The cameras will start taking pictures of a vehicle's number plate the moment the signal turns red, sources said.

The cameras will perform three roles rolled into one, a senior officer said.

All the cameras being infrared, they will be able to capture images in the dark. Second, the system will function on the principle of red-light violation detection. This means that they will be activated when the signal turns red.

The moment the cameras are activated (after a signal turns red), they will start functioning as an automatic number-plate recognition device that instantly captures the registration number of any vehicle crossing the stop line when the signal is red.

The data collected from these cameras will be used along with the existing database of vehicle owners. Once a vehicle is caught violating a signal, a challan will be generated against that registration.

One-third of fatal accidents occur between 10pm and 6am. Traffic cops are withdrawn after 11pm, leaving roads under the watch of the local police station.

Howrah and Bidhannagar police have been using night-vision cameras to book traffic violators for more than a year.