"Smart motorways deliver similar benefits to conventional widening but at a significantly lower cost and with less impact on the environment during construction. A smart motorway scheme can be delivered in less time that conventional widening"
"Implementing smart motorways on the M60 in Greater Manchester will reduce congestion and make journeys more reliable. This in turn creates economic benefits for the region and the country as a whole.
We already have evidence of the benefits that a smart motorway scheme can bring. The first smart motorway scheme (known then as a managed motorway) opened to traffic on the M42 motorway in 2006. Recent analysis of the data gathered since opening has found that journey reliability improved by 22 per cent.
In addition, personal injury accidents have reduced by more than half since hard shoulder running was introduced. There was also an overall reduction in the severity of accidents with zero fatalities and fewer seriously injured"
That all sounds sensible enough to me!
http://www.highways.gov.uk/roads/road-projects/m60-junction-8-to-m62-junction-20/