Mini Roundabouts
A General Guide
Introduction
Mini-roundabouts were first used in the 1970s as a 'priority to
the right' control to be introduced. This was implemented at
junctions where the conventional roundabout, with a kerbed central
island, could not be accommodated. More recently it has been
recognised that they also provide an effective form of traffic
calming, reducing some vehicle speeds and often reducing
accidents.
While they may be considered at any junction they generally work
best at three-armed junctions and they should only be installed in
areas where the speed limit is 30mph or less, and where street
lighting is present.
Double mini-roundabouts may also be installed where junctions
are staggered.
Physical Appearance
The physical construction of a mini-roundabout may consist
of:
-
Slightly raised or flush central island measuring 4 metres or
less in diameter, allowing for the over-running of larger
vehicles.
-
Arrows to indicate the direction of traffic around the central
island.
-
Signing in advance and at the
mini-roundabout.
-
Kerb build-outs and refuges designed to align traffic and reduce
speed thereby improving pedestrian safety.
Advantages
- Can be introduced within the existing highway
boundaries.
- May be cheaper to install than some other conventional
measures.
- Are effective traffic calming measures, reducing vehicle
speeds.
- May reduce accidents and accident severity, by reducing
speeds.
- Allow traffic to emerge more safely from the side
road.
Disadvantages
- It is not always possible to provide satisfactory pedestrian
crossing points in close
proximity.
- Cyclists may experience difficulty in negotiating the
mini-roundabout.
- Noise and pollution levels may be slightly
increased.
- Driveways in the area of the roundabout may experience access
problems.
- Parking restrictions may be required to prevent obstruction.
This would require a
Traffic Regulation Order (TRO).
- May attract additional through traffic due to improved traffic
flow.
Surveys and engineering investigations must be carried out to
determine that the disadvantages do not outweigh the
advantages.
This information has been reproduced by kind permission of
Bristol City Council
