Roads - Speed Limits
A General Guide
The Effects of Speed Limits
Speed limits other than the national speed limit can be
introduced by the Council by the promotion of a
Traffic Regulation Order (TRO). The Department for Transport (DfT) consent is
required for limits on trunk roads in certain circumstances.
It is recognised that speed limits on their own do not
necessarily reduce the speed of vehicles, particularly if they are
set at a level substantially below that at which the majority of
drivers would choose to drive. Therefore, lower speed limits do not
necessarily result in lower speeds.
To effect this, the character of the road needs to be altered.
Measures other than signing are required if speeds are to be
reduced to a level where drivers understand and accept the need for
the limit. Police enforcement can then target those irresponsible
drivers. The main benefits of a speed limit can be:
-
a reduction in the number and severity of accidents
-
reduced emissions and traffic noise
-
improvement in amenities
-
improved conditions for pedestrians and cyclists
-
a reduction in perceived risk by local people
The disadvantages include:
-
possible increase in delays to traffic
-
need for and cost of enforcement
-
visual intrusion of signs / road markings in environmentally
sensitive areas
Variable Speed Limits
These vary by time of day or according to traffic flow
conditions. Typical uses would be outside schools or as part of a
speed / flow management scheme such as on the M25. These types of
limits also require DfT approval.
Advisory Speed Limits
These indicate a maximum speed that is considered appropriate
for the prevailing road conditions. These could be at road works or
in the vicinity of a school and are not subject to police
enforcement. Sometimes an advisory maximum speed is signed at
isolated hazards, such as a tight bend.
20mph Limits and Zones
Below 30mph the only limit which can be introduced without
special consent of the DfT is 20mph.
Speed Enforcement Cameras
These are proving to have a significant effect on vehicle speeds
and accident rates. Their use is restricted because of the high
costs involved and the difficulties of administering
prosecutions.
Speed cameras, both static and mobile, can have a significant
effect on vehicle speeds and have been proven to reduce accidents
where they are used. Speed cameras in Bath & North East
Somerset are controlled by the Safety Camera Partnership which is a consortium
covering the old Avon area, Somerset, and
Gloucestershire.
Speed Warning and Message Signs
These inform drivers that they are travelling at an
inappropriate speed. Their use is increasing and the objective of
this initiative is to influence driver behaviour by a combination
of a media-based awareness campaign and high profile monitoring and
enforcement.
This information has been reproduced by kind permission of
Bristol City Council
