M42 motorway

The M42 motorway is a major road in England. The motorway runs north east from Bromsgrove in Worcestershire to just south west of Ashby-de-la-Zouch in Leicestershire, passing Redditch, Solihull, the National Exhibition Centre (NEC) and Tamworth on the way. The section between the M40 and M6 road forms – though unsigned as such – a part of Euroroute E05. Beyond junction 11 the route is continued as the A42, the junctions on this section, 12-14, are numbered as a continuation of the motorway.

Planning and construction
The M42 was first announced in 1972.

The first section opened in November 1976 linking Birmingham International Airport with the M6 motorway.

The curve around the south-eastern side of Solihull opened in September 1985 followed by the section from the M6 motorway with the A5 at Tamworth in December 1985. The southern section of the motorway to Alvechurch just north of Redditch to form a junction with the A441 and from A5 at Tamworth with the A444 at Measham opened in 1986.

In 1987 the section to the A38 at Bromsgrove, some 15 mi south of Birmingham was completed. and then in December 1989 the motorway was completed with the opening of the link from the M5.

Operational history
The section of the M42 between junctions 7A and 9 was re-built as part of the M6 Toll works and now forms the link between the M6 and the southern end of the toll road.

The section of road between junctions 3A (M40) and the M5 was going to be renumbered as part of the M40 when it was extended to Birmingham, and the junction was built with priority going to the now westbound section of the M42 and the M40 towards London. However when the junction was opened, no renumbering took place.

The M42 was originally planned to extend all the way to the M1 near Nottingham, though this was never constructed, and the A42 link was constructed in its place.

Birmingham Motorway Box
Along with sections of the M5 and M6, the southern sections of the M42 form an orbital motorway around Birmingham. Much like the M25 around London, and the M60 around Manchester, there are areas where this orbital system does not work well. One such point is junction 3A, the link between the M42 and the M40, where traffic is often heavy in the rush hour. The intersection between the M42 and M6 is often very busy too, especially when travelling along the M6.

Active Traffic Management
The Highways Agency is implementing an Active Traffic Management (ATM) system between junction 3a and 7 of the M42. This is a scheme which combines a number of new technologies with some tried and tested motorway traffic management techniques. The scheme includes mandatory variable speed limits, as on the M25, enhanced driver information signs and a new congestion and incident management system. This system allows operators to open and close any lane to traffic in order to help manage congestion or an incident. This includes using the hard shoulder as a running lane between junctions under controlled conditions. This has proved very successful, with journey times decreasing by 26% northbound and 9% southbound. Drivers can also better predict their journey times as the variability decreased by 27%. The government announced in 2007 that the system will be expanded to the M6, with a feasibility study to be undertaken to determine other likely motorways where this technology can be implemented.

Journey time trial
The latest scheme to be tested on a long gently climbing stretch is one in which eastbound HGVs are not allowed to overtake during daytime hours. This scheme was implemented because the route is often congested on account of the motorway having only four lanes (two lanes in each direction) as it leaves the West Midlands.

Junctions
Data from driver location signs are used to provide distance and carriageway identifier information. If a junction extends over several hundred metres and both start and end points are known, both are shown.