A smart motorway (formerly managed motorway and active traffic management), also known in Scotland as an intelligent transport system, is a section of motorway in the United Kingdom (primarily in England) that employs active traffic management (ATM) techniques to increase capacity through the use of MIDAS technology including variable speed limits and occasionally hard shoulder running and ramp metering at busy times. They were developed at the turn of the 21st century as a cost-effective alternative to traditional carriageway widening, with intended benefits ranging from more reliable journey times to lower vehicle emissions. However, despite the risk of a collision occurring between two moving vehicles being found to be decreased, there has been an acknowledged rise in the incidence of c