Samenvatting
The M25 Orbital Motorway that encircles London is infamous for its tailbacks that can often snarl up several of its 30 junctions. This, though, is about to change with the Highways Agency's (HA) 2005/2006 Business Plan. The plan, for which new technology is a cornerstone, includes projects such as Controlled Motorway, Active Traffic Management (ATM) and the use of a High Occupancy Vehicle (HOV) lane as planned for the M1. This document describes Controlled Motorways, the basic principle of which is congestion management using variable speed limits to harmonise speed across the lanes. Speed limits are set automatically using data from MIDAS loop detectors embedded in the road surface. For the covering abstract see ITRD E139966.