M42 Motorway, Active Traffic Management and Speed Cameras

40MPH Speed Limit SignA mandatory 40MPH sign greeted me as I joined the M42 motorway on my daily commute to work this morning. It’s part of an £100M advanced scheme to improve the flow of traffic on a congested stretch of motorway, with the possibility of it being rolled out to other areas if successful. This is the first day of the Active Traffic Management operation.

Active traffic management has been installed between junction 3a and junction 7 of the M42. This is from the junction with the M40 to the junction with the M6, and includes traffic passing around Birmingham; traffic to and from Birmingham Airport and the NEC with major events such as the Motor Show, Caravan Boat and Leisure Show and the Ideal Home Exhibition.

The active traffic management includes electronic signs every few hundred yards with variable speed signs and speed cameras. The variable speed now displays using a red circle around the speed indicating that the speed limit is mandatory, and not advisory as on most other motorway signs. This is similar to the system currently installed on some parts of the M25, London orbital motorway.
The highways agency website says that they don’t plan to use the cameras to enforce the 70mph national speed limit when the signs are not in use, although it is carefully worded to not exclude using it for that in the future. The consultation process did look at using the cameras to enforce the 70mph national speed limit.

The variable speed limit signs are turned on and the speed adjusted automatically as congestion is detected on the motorway. This is achieved using induction loops at regular intervals in each of the lanes including the hard shoulder.

Another new feature of the system is that emergency refuge areas have been created at regular intervals on the motorway. In the event of a breakdown or emergency, vehicles should go into these areas for recovery or to await assistance, rather than stopping on the hard shoulder. This means that the hard shoulder can be used as a running lane, when the traffic is particularly congested (so far this has not been used). This is controlled using the overhead signs.

This morning I joined the motorway at junction 6, the NEC / Birmingham Airport / A45 junction and the speed limit was already set at 40mph. After passing one more sign set to 40mph, the next sign showed 50mph and shortly after went up to 60mph. As we neared the Solihull turning the speed dropped to 50mph, and then afterwards went back up to 60mph, where it remained until the end of the active traffic management where the last sign was back to the national speed limit.

The traffic was flowing quite well, in most cases running just a few miles per hour less than the signed maximum speed limit. Heading southbound in the mornings is not normally too busy, but the northbound traffic also appeared to be moving quite well, which often struggles in the morning. For me the real test will be driving home this evening when congestion is likely to be worse.

One thing that I did notice is that you have to be actively watching the signs to make sure that you don’t miss the changes in speed limit. It would not be too hard to miss a change in speed limit and so inadvertently get caught by a speed camera.

So far so good, but I’ll be traveling over that stretch on a daily basis and will update my blog to show how well it is working.