The Mayor's Ambient Noise Strategy - Greater London Authority

84 Mayor of London
The Mayor’s Ambient Noise Strategy
Such improvements will allow buses to run more smoothly with less ‘stopstart’
noise. Transport for London will continue to improve bus journey
times and reliability through major bus priority programmes of works and
enforcement. TfL London Buses is also encouraging better driving through
sponsoring a BTEC training scheme for drivers. This will, among other
things, encourage smoother, quieter driving.
Box 30: Buses and traffic noise
Bus noise should not be looked at in isolation. Using buses for journeys
which would have taken place using many individual cars or other
motorised vehicles, and using them as part of a network which also
encourages walking and cycling, can contribute to an improved noise
environment overall. Changes in noise as a result of increased bus
services, but fewer cars, will vary between different links in the road
system. The changes depend on a range of factors, some of which can be
more readily predicted than others. The mix of buses, cars and other
vehicles will vary substantially between different streets, as will the speeds
of vehicles. The introduction of newer buses should mean a quieter fleet
overall, due, for example, to newer engine technology. See also box 31 on
trialling new fuel cell buses.
4A.54 Modern buses have been becoming generally quieter. With many of
London’s streets in poor condition after decades of under-investment,
buses jolting over uneven road surfaces can generate more noise than
they should. However, since most modern buses use air suspension
systems, they are less likely to generate the types of body noise
associated with commercial vehicles with loose body fittings, or nonisolated
steel suspension systems. Traffic congestion disrupts schedules
and increases the pressure to drive faster when traffic is clear. The bus
priority measures which the Mayor is pursuing to protect buses from
congestion, will enable smoother, quieter bus driving. As London’s bus
fleets are further modernised, and as conditions for bus driving improve,
with more bus priority, less congestion, properly maintained streets and
adequately paid, motivated and trained staff, conditions should improve.
4A.55 A high priority has been given over recent years to how London buses can
contribute to better air quality. Many of these measures also reduce noise.
Bus engines which use gas can be substantially quieter than traditional
diesels. TfL London Buses currently operates three liquid petroleum gaspowered
buses, though fuel and capital costs have not incentivised takeup.
Alternative fuels are being actively reviewed. A London Bus Testing
Cycle, developed for air quality testing purposes in conjunction with
Millbrook Proving Ground, indicates buses are idling for 31.5% of the
time, and decelerating for 27.5%. This could make some form of hybrid