Alternatives to charging
117. The Secretary of State's guidance states that
studies should produce a strategy of how to proceed without charging.
Many of the studies have suggested that if charging is not introduced
then intelligent motorway control systems could reduce congestion.
Such systems include Variable Speed Limits such as those on the
M25 north of Heathrow Airport and 'ramp metering' where traffic
lights on the slip roads control entry to the motorway.
118. The Highways Agency told us that ramp metering
had shown benefits in the US. Trials on the M6 and the M27/M3
have been undertaken. However it told us that "it is not
yet possible to conclude whether ramp metering is providing benefits".
Ramp metering may also cause problems for the surrounding network
if queues on the slip road reach back to the roundabout. This
limits the scheme's effectiveness. The Variable Speed Limits in
operation near Heathrow has received significant driver support.
However, the Highways Agency note that "detailed monitoring
and analysis of traffic flows, speeds and accidents has so far
not demonstrated overall benefits relative to costs".
119. It would be nice if technology were to provide
the answer to our congestion problem. However, the conclusions
of the studies show that whilst these new systems may show some
benefits, they are relatively small and will only have an impact
over the short-term. Technology will make a significant but small
contribution to reducing the daily congestion on our motorways.
It should not be relied on as an effective alternative to inter-urban