2014年经济学人 智能高速 道路开拓者（在线收听）

Smart motorways

Tailblazers

How to make life easier for motorists without building new roads

IDLING on a motorway for an hour or two has long been a part of any British summer holiday. But this year fractious drivers on the southern strip of the M25, an orbital road around London, may have some respite. In April part of the road, between junctions five and seven, opened as a “smart motorway”. It is one of around a dozen projects currently being undertaken by the Highways Agency, the body which manages Britain's motorways and trunk roads. The scheme is an innovative way to reduce congestion cheaply. But it is also a striking example of how the government is quietly making life easier for motorists.

Britain's roads have been creaking for years. According to the World Economic Forum, its lanes are worse than the underfunded stretches of tarmac in America. Spain and Portugal—two countries which suffered far more during the financial crisis—score higher. Funding is part of the problem: cash for maintaining major roads has halved since 2010. But motorways in Britain are particularly jammed. Although the number of people driving in cosmopolitan areas such as London is shrinking, the rise of online shopping and a growing population are pushing more delivery vans and cars on to busy roads.

Rather than spend lots of cash laying more tarmac, however, the Highways Agency has sought to invest in other ways to reduce congestion. In 2006 the Labour government ran a pilot programme, known as an “active traffic management” system, on part of the M42 in Birmingham. The scheme placed gantries with electronic signs every 500 metres along the motorway, installed CCTV cameras and allowed the hard shoulder to be used as an extra lane at busy times, boosting capacity by around a third. A variable speed limit was introduced, determined by sensors. Making cars travel at a slower, more uniform speed means more can be squeezed on the roads.

Since then the project, now known as “smart motorways”, has become more ambitious. On certain roads the hard shoulder can be used as a fourth lane at all times. Rather than plaster a motorway with words in flashing lights, more effective signs with pictures are now in use, says Graham Dalton, the chief executive of the Highways Agency. This means that non-English speaking truck drivers are more likely to take note, he adds. Future schemes may also have fewer emergency lay-bys, after it was found that many Britons used them to fiddle with their phones or for a toilet break.

Elements of smart motorways have long existed elsewhere. But Britain has taken the idea further, says Mr Dalton. In the Netherlands and Germany an extra lane can be used at peak times, while a few flashing signs may also manage traffic. But Britons appear to need a shove, not just a nudge.

Motorists should expect more of this: politicians like the scheme, which is far cheaper than traditional road-widening programmes. The M25 programme cost 129m. By contrast, adding more lanes between four junctions on that motorway cost 361m. And the government is adopting a friendlier stance towards motoring groups. The budget for the Highways Agency is projected to double under the next government. Flush with cash, the smart motorways scheme may move into second gear.