Intelligent transport systems (ITS) are being introduced to reduce congestion and pollution and to improve traffic flow and safety for road users. ITS relies on a high-speed communications network. ITS can help reduce the need for further road construction by improving the capacity of the existing infrastructure. Investment in active traffic management (ATM), where the emergency lane on a motorway is opened to traffic, is less costly than new road construction. In the UK, part of the M42 has been upgraded with ATM. This required the installation of new gantries supporting lane specific signals and driver information panels, new emergency refuge areas, new safety fencing, and new fixed CCTV. In tunnels, the main focus of ITS is in fire safety. CCTV, intelligent signage, fire sensors, fire control systems and in-tunnel communication are important elements of a tunnel fire safety system. ITS has been shown to reduce the accident rate in the Netherlands and the UK. The components of an ITS system are described. The design of a transmission and access system is illustrated by Merseytravel's Internet Protocol IP network.
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