I was driving on the M1 motorway recently when I noticed something I had never recognised on previous journeys.
My first experience of anything other than a traditional motorway was on the M42 near Birmingham from Junctions 3A to 7. Installed in 2005 it seemed to work well at times of peak traffic when congestion and static traffic meant you could take a lengthy period of time to travel a few miles between where the M40 and M42 roads merge and the M6 interchange.
Since then the term 'smart motorway' has come to describe three distinctively different versions of what is known as Active Travel Management (ATM.)
The common denominator is that all types use CCTV, radar and sensors to monitor traffic flows. In the case of congestion or an accident, speed limits can be varied and, where necessary, lanes closed. The section of the M42 Junctions 3A- 7 is designated 'dynamic hard-shoulder running', where the hard-shoulder can be opened up at peak times and used as an extra traffic lane.
'Controlled motorways' keep the hard-shoulder at all times and only use variable speed limits to manage traffic flows. Existing gantries are upgraded to support signs capable of displaying a mandatory speed limit and speed cameras.
The most contentious type of smart motorway is known as 'All lane running' where the hard shoulder is permanently converted into a live lane. There have been a number of fatal accidents where drivers of broken-down vehicles were unable to get to one of the refuges spaced at intervals along the stretch of all-lane running motorway.
What I noticed on one of these sections of smart motorway was that gantries were few and far between , unlike on the M42. Like most drivers, I would find breaking down in a live lane of any smart motorway daunting, but the realisation that other drivers would not be advised by signs on the over-head gantries to slow down and avoid the affected lane makes me wonder how these schemes ever gained approval.
