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What are "smart motorways"?

Today, Deputy Prime Minister Nick Clegg announced a giant collection of road improvement measures across the UK. He celebrated with a visit to, er, Stonehenge:

The list of 80 upgrades include many that seem like obvious choices: improving road surfaces, widening existing roads, a new tunnel at Stonehenge.

About 30 miles worth of M4 and a stretch of the M62 between Manchester and Leeds, however, are due to be transformed into “smart motorways”. So what exactly is a smart motorway, and what’s the point of installing them? Here’s all you need to know. 

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They’re not really that smart. 

They sound fancy and futuristic, but in fact, smart motorways are generally just roads with illuminated signs, which allow the hard shoulder to be used as an extra lane at certain times. The same signs also allow the Highways Agency to set variable speed limits, give warning of incidents up ahead, or use crosses to show when a lane is closed: 

In fact, until “smart” became an acceptable prefix for pretty much any product on the market which uses electricity, these roads were known as “managed motorways”. 

You’ve probably already been on one. 

Smart motorways already in operation on small sections of the M1, M4, M5, M6, M42 and M62 motorways, and opeate in a more limited way on the M6, M20 and M25. This helpful map, courtesy of Fleet News, shows the existing and planned “smart” roads in England (it was created in May so is slightly out of date, but you get the idea): 

They’re expensive. 

The combined cost of roadupgrades announced today across the UK is £15bn. The conversion of 32 miles of the M4 alone into a smart motorway would cost £750m, 5 per cent of the proposed sum. It will also require the replacement of 16 bridges (in order to install all those signs), and will apparently take at least five years to complete. 

However, cheerleaders for smart motorways argue that the cost allows for an extra lane, which would come at a far higher price it if were achieved through raod widening. They’re also less destructive than the construction of new roads to take pressure off motorways.

As Stephen Glaister, director of the RAC Foundation told ITV today

This is not about concreting over the countryside with new roads but upgrading many existing routes which have been the source of misery to motorists for years, if not decades. That the government is investing money along whole lengths of roads and not just a mile or two here and there is to be welcomed.

They could help Britain’s regions realise their “full potential”. 

Well, according to Nick Clegg, at least. Today, in an impassioned statement on the 80 road upgrades, he said:

For too long, our road network has been a source of frustration, not growth. There are whole regions of our country that are unable to reach their full potential, let alone get to work on time, because the essential routes that link them to the rest of the country are way past their sell-by date.

To build a stronger, fitter economy in Britain, where every region can thrive, we need to… [give] our regions’ most strategic roads the serious investment and attention they deserve.

Past governments have done it for the South East. I want to do it for the rest of the country.

He’s like a Batman for the provinces, isn’t he. Bless him.

So, there you have it: next time you see an “incident up ahead” sign or a glowing speed limit, know that you’re driving along a road of the future. 
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