UK looks at alternatives to building a way out of congestion
November 26, 2004
BBC (United Kingdom)
Congestion on England's trunk roads and motorways could be cut with a little creative thinking, according to a new report. How?
Drivers brace yourselves: congestion on England's major roads is increasing while plans for tackling the problem remain up in the air.
As government strategists return to the drawing board for the third time in four years, seeking to revise targets for cutting congestion, measures to cut jams have suffered, according to a new report.
Traditionally, governments have sought to build their way out of the problem - expanding roads to cope with the rise in cars. But a new report, drawn up by the National Audit Office, has highlighted a number of simple, but more creative alternatives.
A fancy name for reversing the flow of traffic in one or more lanes during peak periods. Signals above the carriageway indicate which lanes are in use and the direction of traffic in those lanes. For example, a four-lane carriage way - two lanes in each direction - could be altered to allow three lanes in one direction, with just one going the other way.
Introduced in the 1970s, the system is well used in Holland and Germany as well as the US, Canada and Australia. So far, it is only found on a handful of trunk roads in England. Officials claim it is most effective on busy urban roads, to cope with morning and evening rush hours, but there are safety worries about fast traffic running in opposite directions without barriers to divide it.
VARIABLE SPEED LIMITS
Speed limits are adjusted depending on traffic volumes and weather in order to smooth flow, cut accidents and so reduce congestion. Traffic flow is monitored by electronic devices buried in the road and limits are signalled by displays on overhead gantries. It works by reducing heavy braking, stopping cars bunching together and so forming jams.
Compulsory variable speed limits currently operate on 30km of the western section of the M25 - London's orbital motorway - while advisory limits are found on 30% of the wider motorway network.
Results from the M25 have been positive, reporting a cut in serious accidents of 10-20%, but England still lags behind other European countries. Half the motorway network in Holland uses variable speed limits.
Currently being trialled in the Netherlands and Germany, this measure aims to reduce congestion during peak periods by increasing the number of lanes. Lights, similar to cats eyes, are set into the road and can be turned on or off to mark out lanes. Thus three normal lanes could be turned into four narrower lanes at the flick of a switch.
Although bus lanes are a common sight on Britain's urban roads, they are rare on motorways. The M4 bus lane, which opened in 1999 and runs close to Heathrow airport, did not go down well with motorists although studies later showed it made car journeys slightly quicker during peak times. Off-peak journey times increased slightly, and there was a 20% cut in accidents.
Another sort of dedicated lane, pioneered in the United States, is the HOV - high occupancy vehicle - lane, in which only cars with two or more people can travel. The idea is to reduce congestion with commuter car sharing and, in places such as Washington DC, it's taken off so well that commuters line up to hitch rides with lone drivers, in a practice known as "slugging".
In the Netherlands HGVs can't overtake on the vast majority of the motorway network, in effect making the inside lane a dedicated lorry lane.
Again, common in the US, ramp metering involves traffic lights on slip roads that lead on to motorways. By controlling the rate cars joins a carriageway, traffic surges can be ironed out, cutting congestion and accidents. It was introduced on parts of the M6 almost 20 years ago and cut journey times by up to 20 minutes.
However, the technique was not rolled out. Officials said the junctions in question were unique and ramp metering would not be as effective at other junctions. There have also been trials on the M27 and M3.
HARD SHOULDER RUNNING
In effect widening the road by opening up the hard shoulder to normal traffic. The Dutch and Germans have used this technique since the 1990s but in England it has been resisted by the emergency services which have concerns about how they would reach an accident site.
Where this works on the continent, speed limits are cut and frequent refuge areas are provided for motorists in trouble. Research has found that accident rates have fallen where this scheme is applied and the Highways Agency has recently embarked on a trial.
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