HADECS Camera Testing Underway

The Forth Replacement Crossing (FRC) project created a 13.7 mile (22km) ‘managed motorway’ by using an Intelligent Transport System (ITS) to help regulate the flow of traffic approaching and crossing the Forth.

This is the first time such a system has been used in Scotland, though similar managed motorways have been successfully implemented in England, for example on the M42 and M25.

The project opened in phases – starting with phases 1 (Fife) and 2 (Edinburgh, West Lothian) which opened in the winter of 2012 with the third and final phase opening with the new Queensferry Crossing on 30th August 2017.

ITS now extends along a 22km corridor from the M90 Halbeath Junction over the Queensferry Crossing to the M9 north of Newbridge Junction.

Drivers require no specialist skills to use roads featuring ITS.

Overhead gantries are spaced regularly along the ITS corridor and provide lane control, variable mandatory speed control and bus lane control. Variable message signs on the gantries provide drivers with a wide range of traffic information.

Mandatory variable speed limits are applied when necessary - e.g. during incidents or when significant congestion occurs.  The speed limits will be enforced.


  • There is clear evidence from similar schemes in the UK and across the world that Intelligent Transport Systems increase road operational efficiency, capacity and safety.
  • During incidents or periods of congestion when demand exceeds capacity, the system  sets signals and message signs to inform and advise drivers to effectively manage incidents and reduce queues
  • Variable mandatory speed control  help maintain a steady flow of traffic and limit congestion to make journey times more reliable
  • Evidence indicates that systems which reduce vehicle queues can reduce accidents resulting in injury by up to 13%

Speed Limit Enforcement

Enforcement equipment for the Variable Mandatory Speed Limits (VMSL) comprises HADECS3 (Highways Agency Digital Enforcement Camera System v.3) enforcement cameras and has been installed at 6 locations on the M90 between J3 Halbeath and J1A Kirkliston.

All cameras are currently being subjected to a testing exercise to assess system operation and performance. As part of this, road users may see the cameras flash but offences are not being generated during this testing phase. However, in the interim period, speed limits continue to be enforced by Police Scotland patrols.

A further communications campaign will commence in advance of camera enforcement. This will inform road users when camera enforcement comes into effect and how the system operates.