Page 5: Technological factors
Using technology helps the Highways Agency respond to challenges posed by political, economic and social factors:
- The Agency uses an array of technology to monitor and control road traffic. CCTV is used to monitor conditions on the road network. Control room staff across the country use sensors in the road surface and over 1,200 CCTV cameras to quickly identify any emerging problems. Information is shared with broadcasters such as the BBC to keep drivers informed. In the event of an incident or breakdown, control room staff can quickly direct Traffic Officers to the scene.
- Over 1,200 kilometres of the motorway network are now covered by the Motorway Incident Detection and Automatic Signalling (MIDAS) system. This consists of sensors in the road surface, spaced at intervals of around 500 metres, which can detect slow moving or queuing traffic. The electronic signs on the road then automatically display reduced speed limits and messages such as 'QUEUE AHEAD'. The idea is to warn drivers that there may be slow moving traffic ahead so that they can slow down and avoid having an accident. On some motorways this is taken a stage further by setting compulsory variable speed limits. This system helps to keep motorists driving at a speed which the system has calculated as the best speed to keep the traffic flowing. In the Active Traffic Management system it is also used to calculate the best time to open up the hard shoulder as an extra lane to help keep the traffic moving.
- At the end of March 2009, over 85 busy junctions also now have ramp metering, which uses traffic lights on entry slip roads to control the flow of vehicles on to the motorway. It lets vehicles onto the motorway a few at a time to prevent traffic building up. The Agency is investigating other locations where ramp metering can help to reduce congestion.
- By giving road users the latest information on traffic conditions they can choose to take another route, allow extra time and/or delay their journey. The Agency helps by giving motorists the most up-to-date information where and when they want it: via its own DAB digital radio station, Traffic Radio, which is also available online, information points at some motorway service stations and via its Traffic England website or the 'mobile-friendly' website.
- On the road itself, the Variable Message Signs (VMS) system displays live messages to road users telling them how long it will take them to drive to certain key motorway junctions in the current traffic conditions.