Driver training specialist IAM Drive & Survive is offering weekly motoring tips to drivers from its head of training, Simon Elstow. This week he is advising on managed motorways.

“Managed Motorways” is the term for variable speed limits, sometimes in conjunction with opening the hard shoulder to traffic at peak times. The IAM says that managed motorways are very successful: the first one was the M42 near Birmingham, in 2006, and it has shown a decrease in personal injury crashes of more than half, none of them fatal.

The key to the system are the signs on the overhead. The six signals are:

• A red cross without flashing beacons. The hard shoulder is only for use in an emergency or breakdown.

• A speed limit inside a red circle. It is absolutely mandatory and may have cameras enforcing it.

• A blank signal. Usual motorway rules apply.

• A white arrow with flashing beacons. This applies to all lanes and means you should move into the lane which the arrow points to.

• A red cross with flashing beacons. You should not continue to use the lane.

• A national speed limit sign is shown. The national speed limit, 70mph maximum, applies to all lanes apart from the hard shoulder.

Elstow said: “Managed motorways not only help keep motorways moving – they are also safer than conventional ones. Their numbers are set to continue, so brush up on your knowledge of the signs so you can get the biggest benefit out of the information they are giving you.”