The Highways Agency Digital Enforcement Camera System 3 (HADECS3) is manufactured by Redflex Traffic Systems. All HADECS 3 cameras operated by the SEU have been installed by Redflex who also perform the calibration testing, any required maintenance and back office operator training.
The HADECS3 speed camera system has Home Office Type Approval for use in detecting and recording evidence of speeding offences on a SMART Motorway in conjunction with Advanced Motorway Indicator (AMI) signs. A copy of this approval can be viewed here: HADECS3 HOTA
The HADECS3 camera system has been designed to accurately measure the speed of vehicles on a SMART Motorway where the speed limit may be reduced from the National Speed Limit (NSL) of 70mph. The current speed limit is indicated on the AMI signs which are mounted on overhead gantries. For a reduced speed limit this would be in the form of mandatory speed limit signs with a red ring. If the NSL is in place it can be indicated by an NSL sign or the AMIs being blank.
HADECS3 cameras are mounted at the side of the gantries. They monitor traffic over the full width of the carriageway and are able to symultaneously detect speeding offences in all 4 lanes. They are connected to video cameras that monitor the AMIs and use character recognition software to read what speed limit is displayed on them. The HADECS3 cameras will only enforce the speed limit when they have confirmation that all of the AMIs above open lanes are correctly indicating the current limit.
There is a 1 minute grace period following a change of speed limit being displayed during which time the HADECS3 camera will not enforce. This is to allow drivers who approached the gantry as the signs changed enough time to safely reduce their speed if they need to do so to comply with the new limit.
If the camera system detects a vehicle is travelling above a preset threshold for the current speed limit the camera is triggered. It then records three images and data of the offence which is transmitted via a secure connection to the SEU office for processing. Every offence is manually checked by a trained member of Police Staff before a Notice is issued to the vehicle's DVLA registered keeper.
Each HADECS 3 camera has been installed and tested by Redflex who issue a Calibration Certificate to confirm that the camera is working correctly. They also perform annual calibration testing.
Each time the camera is triggered it records two wide view images of the road so a secondary check of the vehicle's speed can be made by measuring how far it has travelled. A trained member of Police Staff confirms that the result of the secondary check is within the HOTA required tolerance of +/-10% of the primary speed reading before a Notice is issued.
Specialist back office software is used to measure how far the vehicle has travelled. Any check marks visible on the road surface are left over from the previosuly installed HADECS 2.0 system and are not used by the HADECS3 system.