Plans for M20 Variable Speed Limits Condemned
The Association of British Drivers denounces Highways Agency plans to impose variable speed limits on part of the M20 as an unnecessary burden on drivers and a waste of money.
The proposed 'controlled motorway' scheme between junctions 4 and 7 will see mandatory speed limits, varying according to traffic flow, enforced by digital speed cameras. The scheme, which will cost £12.4 million initially and a further £240,000 per year to run 1
, is intended to promote smoother traffic flow at peak times, but experience of similar schemes already in operation is not encouraging.
The Highways Agency used the variable speed limit scheme between junctions 15 and 16 of the M25, which was introduced in the mid 1990s, to calculate the expected benefits of the M20 proposal. But the M25 scheme has not led to any improvement in journey times overall, and only a small improvement in journey time reliability. Although it is claimed to have reduced injury accidents by up to 15 per cent, it is not clear whether this finding took into account long-term accident trends or the increased underreporting of non-fatal accidents, which have given rise to false claims that national casualty reduction targets are being met.
There are also concerns that the automatic detectors used to measure traffic flow and vary speed limits accordingly are not as reliable as the Highways Agency claims. In practice, low speed limits are sometimes imposed when traffic conditions do not warrant them. This applies not just to the M25 scheme but the more recent 'active traffic management' scheme on the M42 in the West Midlands, which incorporates hard shoulder running as well as variable speed limits. The ABD's environmental spokesman, Paul Biggs, comments:
“I use the M42 and M6 regularly during off-peak periods when traffic is light, so there should be no need for the variable speed limits to be activated, but limits of 50 or 60 mph are often displayed. This is very frustrating and refutes the Highways Agency's assurances that speed limits will always be matched to the road conditions.”
The Highways Agency undertook a public consultation on the proposal last year and the results have just been published 2
. While 41 respondents were in favour of the scheme with 32 against, it is clear from the analysis of the reponses that there was a co-ordinated campaign by anti-roads and environmental groups to influence the result. For instance, 44 per cent of those in favour said that reduced noise pollution was the most desirable feature of the scheme, despite the reduction in noise level from the earlier M25 scheme being too small for the human ear to detect. Another 33 per cent rated reduced carbon emissions as the greatest benefit, but these would also be very small. Despite the fact that the consultation had obviously been hijacked, the Highways Agency is using the results as evidence of 'much support' for the scheme.
The ABD believes that the claimed benefits of the scheme could be achieved just as well by providing better information to drivers with the latest generation of matrix signs, without the imposition of varying, mandatory speed limits that require drivers to give constant attention to the overhead gantries and their speedometers. As ABD chairman, Brian Gregory, concludes:
“The Government always prefers to regulate and punish drivers rather than change behaviour through persuasion with well directed information. The majority of drivers are responsible individuals and resent the patronising approach of the Government and public bodies. A change in this approach is long overdue.”