The M6 motorway runs from junction 19 of the M1 and the western end of the A14 at the Catthorpe Interchange, near Rugby and Coventry via Birmingham and then heads north, passing Wolverhampton, Stoke-on-Trent, Liverpool, Manchester, Preston, Lancaster, Carlisle and terminating at the Gretna junction (J45). Here, just short of the Scottish border it becomes the A74(M) which continues to Glasgow as the M74. Its busiest sections are J4-10a at Birmingham and J16-19 in Cheshire as this forms the main route from the East/West Midlands and London to Manchester and Liverpool, These sections are now Smart Motorway.