Motorway Gantry Cameras

There are currently two different Gantry Camera systems approved for use in the UK. The first is the old ‘wet-film’ GATSO system (as used on the M25), and the second is the new Highways Agency Digital Enforcement Camera System; HADECS system (as used on the M42).

How they Work

Both systems are used to enforce variable speed limits that are set by the highways agency on sections of motorway.

A variable speed limit is a temporary, compulsory limit set to ease traffic congestion or slow traffic when there have been motorway accidents. They are imposed using electronic signs mounted on motorway gantries, and are denoted by the speed limit with a red circle the maximum speed.

 

Both systems use multiple cameras (one for each lane) mounted at the rear of the gantry usually behind the variable speed limit sign. They use radar for speed detection, and photograph offending vehicles from behind as they pass under and away from the gantry. Gantry Cams are unique in their ability to change their speed threshold automatically, so they match the imposed speed limit and only photograph vehicles exceeding the limit. The cameras are almost impossible for the driver to see and are highly effective at catching speeding motorists.

The difference between the ‘wet-film’ GATSO system and the HADECS system is that the HADECS system is digital and does not run out of film. Captured images are encrypted and sent to the control centre across a network link. GATSOs cameras have to be emptied by hand.

HADECS Facts

RADAR (Kband for speed detection)
Digital Cameras
Linked to Highways Agency Ethernet Network
Manufactured by Variable Message Signs Ltd, UK
Home Office Type Approval (HOTA) November 2006

GATSO™ Facts

RADAR (Kband for speed detection)
Camera containing traditional film /
Model: Type 24 Gatsometer™
Cassettes of 35mm colour film
Enough film for 800 exposures.
Manufactured by: Gatsometer BV in the Netherlands.
Home Office Type Approval (HOTA) November 2000.
Every Gatso™ is sent back to the factory in Holland to be calibrated every 12 months.

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