To ask the Secretary of State for Transport what the criteria are for the use of speed advisory signs on motorways; who is responsible for authorising the (a) operation of such signs and (b) the advisory speed displayed; what mechanisms are in place to provide assurance that such advice is appropriate; and if she will make a statement.
The criteria that are used to set electronic speed advisory signs on the motorway are contained in the Policy and Procedures for the use of matrix signals by the Regional Control Centres which has been agreed between the Highways Agency (HA) and the Association of Chief Police Officers (ACPO). These signs can be set automatically by the system software or manually by the HA Regional Control Centre staff (RCC). The decision to set signals should be based on the information available and is the responsibility of the officer (Traffic Officer or police in charge of the incident at the scene) or the operator in the control room. Where an advisory speed limit sign is set manually by the operator, the decision on the advisory speed displayed is based upon information received from a number of sources including CCTV, traffic officers and police at the scene.
An RCC operator who has set signals manually has to monitor the situation to revise the signal setting as necessary, to prevent the setting of a misleading or contradictory series of signals and VMS messages and remove them when the incident has cleared. The automatic system will clear the signal once the incident has cleared.