Brockley Cross, Lewisham
This is a redesign
of a reasonably successful double mini-roundabout. The present
layout unusually has the yield lines too far forward encouraging
or even forcing straight paths across the junction. My redesign
sets the yield lines back, enlarges the two central islands and
makes more sense of the central dividing island. The object of
the study is to try to reduce the numbers of crashes occurring
although the rate per 100M vehicles crossing is not that high. A
better design with more deflection should improve safety. Local
enhancement of the area is also proposed.
This is a very densely trafficked
site! The traffic capacity is so good that exits are often
observed to block.
The accident rate is not that high but any improvement should
reduce the numbers.
It is unusual at any mini-roundabout to observe the three right
turns occurring at the same time,
but this is happening at the far mini-roundabout.
A larger central island (proposed) enables this to take place
* * * * *
Street/Willersley Avenue, Bexley
roundabout was suggested as part of a Safer Routes to
School scheme in Sidcup, Bexley, first implemented in the summer 2001.
It would have removed virtually all the through traffic past the
schools at their busy times allowing a relatively easy bypass.
Congestion in Willersley Ave (opposite) which was a side-road
prevented easy access to Halfway Street (left - right). The scheme was
introduced only after all the alternative options were rejected.
Hollies Avenue (towards the bottom) might have been closed to
enable a 3-arm mini-roundabout to be installed but local
residents objected strongly. Signals were tested and failed on
capacity grounds. Initially the four-arm roundabout failed an
ARCADY test; however the Sawers formula suggested that there
would be no congestion on the basis of the figures analysed.
Once approved by the council, it was necessary for a special
authorisation as the central island was to be larger than the
standard 4m. The scheme was implemented in June 2005 and has
worked well with only very minor accidents attributable to the
7m diameter central island at crossroads
See www.midi-roundabout.co.uk - image
courtesy of Bexley Council
Note: The central island was intended to be more raised and
have steeper edges;
The very smooth profile has led to much abuse with overrunning
and possibly crashes...
* * * * *
Transport Road Safety Award
|This was the highway part
of a major Safer Routes to School scheme constructed in 2004. Installing the four roundabouts
along Yarnton Way was just one of the innovative
safety features recommended.
It was proposed too that the carriageway should be
reduced to a single lane in each direction and
have cycle lanes added. This reduced overtaking
and provided more space for traffic to wait in
the now widened central reservation crossovers.
An additional Toucan (cycle and pedestrian)
crossing was installed; secure cycle racks were
introduced at Bexley Business Academy, the focal point for
routes to link up with residential areas to the
north remain to be constructed. The scheme is located in a
relatively poor area of North Bexley and received much support
from an initially nervous local populace.
This scheme has
been most successful. The latest is that the local people would
like at least one further roundabout installed on Yarnton Way.
The site may be viewed on PixPlot
- opens in a new window...
Way - the urban dual two-lane carriageway
Lane dualling with four roundabouts
* * * * *
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External links to other sites:
- Getting them right!
The MIDI-roundabout -
minis with larger central islands than standard
This link has now been removed as it is proposed to include this information
the main mini-roundabout site.
In America they have
recently installed "mini-" roundabouts with central islands
considerably larger than we are allowed in the UK.\
I hope to report on these designs as they are most interesting and have been
installed on higher speed roads.
The Americans also publish a
lot of information about their work on the internet.
Rather obviously this remains of considerable interest to me although I am
now unlikely to go there again.
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