The UK government has announced its plans for the national road network in coming years, assigning funding for a variety of different projects. Transport Minister Ruth Kelly has also published plans for a future of "managed motorways", which will require "a high level of monitoring and compliance to make the package work".
"I am determined to get the best from our road network," said Ms Kelly in a statement issued this morning. "The greatest barrier to this is congestion. It is frustrating and has serious consequences for the economy and the environment.
"The £6 billion I am announcing today will allow ... more innovative approaches to the way we use our major roads. This includes measures like opening the hard shoulder when traffic is at its heaviest ...
"Where we add new capacity through measures like this I am also interested to see what role car share or tolled lanes could play in helping traffic flow more smoothly - giving motorists a choice about how they make their journeys."
The government's thoughts were outlined in more detail in a Command Paper, now available for download (pdf). There is a good deal about ordinary widening and construction schemes, and various other measures.
Perhaps the most interesting part of the Command Paper is Chapter 5 - "Towards the Managed Motorway". This discusses the various pilot schemes which have been used on busy stretches of motorway to increase the number of vehicles able to flow through. The aspect of these plans the government prefers to headline is the use of the hard shoulder as a temporary extra lane at peak times.
However, much of the schemes' effectiveness actually comes from temporarily lowered speed limits. Forcing the vehicles to travel slowly reduces the amount of sudden braking which takes place, preventing a strengthening ripple effect moving back along a lane of traffic and bringing it to a halt. If nobody is able to drive faster than, say 50 or 40 mph in dense traffic, the stream of vehicles seldom halts and many more will get past a given point in a given time than if drivers were allowed to go faster.
So far, so good. However, even the normal 70mph speed limit is widely ignored on British motorways, and in order to compel a mass of drivers to go slower still you need to take some fairly draconian steps, as the government explains.
Motorists appear to understand the rationale for the regime, enjoy the improved reliability it delivers, and accept the need for high levels of monitoring and compliance ...
While it is clear to road users that compliance is necessary ... experience tells us that effective enforcement back-up is also needed to maintain high levels of compliance ... So, we need to look at the arrangements that would have to be put in place.
The Command Paper doesn't really specify what these arrangements might be at this point. Schemes thus far have tended to use Automatic Numberplate Recognition cameras (ANPR) to monitor a car's average speed along a stretch of road - and incidentally, to log its presence at a given place and time. This can be useful for other things than traffic enforcement, of course: it's well known that the London Congestion Charge ANPR system is now linked in real time to Met SO15 - the UK's secret terror police.