The management of key road links and crossings typically covers everything from the maintenance of traffic flow to the efficient handling of emergency situations.
Tunnels and bridges, however, present very specific problems of their own, often unique to each installation.
VMS offers a range of special purpose electronic signs to make control facilities available to the tunnel and bridge operator and provide guidance and safety instructions to the user. We see this aspect of traffic management as a natural continuation of the provision of variable message signs for motorway applications and now have considerable experience in developing and providing specialist signs for tunnel and bridge duties.
The demands of bridge management and ferry applications can be very similar to tunnel systems with the added problem of environmental conditions. Bridges are often built in exposed locations and can be subjected to extreme weather requiring reliable monitoring and control systems.
ITS (Intelligent Traffic Systems) technology was developed by VMS to meet such demands, pushing the boundaries of radio data communications and introducing novel advisory needs.
The bridge master is provided with the means to detect weather conditions and traffic flow on or near his bridge and, using variable message signs, he can inform drivers of planned maintenance, traffic conditions and exceptional events; for example, full or partial closures due to high winds.
Our systems are now used on major bridges around the UK, such as the Forth Road Bridge and the Dartford crossing, and as far a field as the Auckland Harbour Bridge in New Zealand.
VMS produce a range of specialist signs for tunnel applications, starting with portal signs for use on the approach and entrance to a tunnel to deliver specific messages.
Lane control signs are used above each traffic lane at the approach or entrance to a tunnel and are repeated at regular intervals inside the tunnel.
Where the speed limit can vary in a tunnel, speed limit repeater indicators are used to allow the tunnel master to vary the speed limit according to traffic and road safety conditions.
We can also offer bespoke solutions to specific problems, e.g. low profile signs for reduced headroom applications, and dual-faced signs for use where tunnels must accommodate contra-flow traffic.
VMS tunnel systems
are in use at Blackwall, Dartford, Hatfield, Heathrow, and the Tyne
Tunnel.
