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Mini-roundabouts - Getting them
Right!
A
vision for the new Millennium
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| Careful
use of mini-roundabouts can hold the key to
making our communities more liveable. In my
experience it has proved possible to achieve good
results in small towns and villages using
mini-roundabouts and traffic calming to make the
whole environment more pleasant for everyone. |
| This
was achieved in Borehamwood, Herts where the
majority of Shenley Road, the main shopping
street, was re-constructed to create a length of
single lane dualling with mini-roundabouts at the
key junctions and speed tables at regular
intervals between. There are no pedestrian
crossings as such but several points where
pedestrians are directed, including of course all
of the speed tables. Pedestrians tend to dominate
in such an environment. |
Shenley
Road, Borehamwood
This scheme won the Urban
Street Environment Award in 1994, below are
two images.
For more information about the
Shenley Road scheme see www.newlifeformainroads.org.uk
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| A general view of Shenley Road
which operates as single lane dualling. This
scheme shows what can be done using physical
layouts. There is not a traffic signal in sight!
It is VERY pedestrian-friendly and has an
excellent safety record. |
A view from the car. These speed
tables, although much improved since my last
visit should in my view be redesigned using
H-ramps to access them; it was noticeable that
car speeds have gone up a bit. I took a bus ride
over the tables and they remain very
uncomfortable. |
High
St, Datchet, Berks
Something similar on a smaller
scale was achieved in Datchet, East Berkshire
where there had been demands for improvements for
many years. Originally the mini-roundabouts were
rejected as they would increase capacity and
hence demand, but some years later their traffic
calming value led to acceptance of the scheme.
Speed cushions have been added to some of the
links to keep speeds down away from the junction
points.
It took many years to
convince the locals of the benefits of a scheme
such as this. But it works!
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| Two
views of The Green, Datchet, East Berks showing
the two mini-roundabouts at a scissor junction.
There is about 50m between the junctions where a
zebra crossing is provided. |
The
traffic benefits of the two mini-roundabouts have
been considerable. Also the village used to
"lock-up" regularly without these and
drivers used to need a "rubber neck" to
emerge safely from the side-roads (on the right
in each case). |
Detailed design of crossroads
There is
great scope for exciting designs of crossroads using a
mini-roundabout, speed table(s) and entry narrowing.
The
alternative is the depressing use of traffic signals or
leaving the junction a priority junction.
I know
which I would prefer!
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Mini- or MIDI- roundabout at a
large crossroads
This
shape is typical of many crossroads in the UK and
also America. I believe this is a way forward
avoiding those unpleasant one-way systems and
making the junction "friendly" for
everyone.
The
whole junction is on a speed table which is
entered over H-ramps or equivalent to make the
vertical shift kinder for buses. Pedestrians are
guided to their crossing points not by
guard-rails but by planting. The yellow areas are
overrunnable in extremis and there are
normal overrun areas on the four corners.
Build-outs shorten the pedestrian routes which
deflect very little from the desire line.
In
this environment parking can take place beyond
the build-outs and a central reservation would
provide easy crossing points for pedestrians and
the whole thing could be landscaped - beautiful!!
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It can be done - how to lay out
a large crossroads for everyone!
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see
www.midi-roundabout.co.uk |
The Future
So,
which way forward for these urban and village
environments?
Do we follow public demand for
"control" i.e. traffic signals at these
key junctions and all that that entails:
- Pedestrian
delays?
- Traffic
delays?
- Ugly street
furniture?
- High
installation and maintenance costs?
- Poor
environment?
- Speeding
traffic on green?
- Pedestrian
accidents?
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| Or
do we appreciate that by keeping speeds under
control it is often not necessary to give
pedestrians and cyclists priority, as the
environment is comfortable enough for them
without it. |
| It
seems to me that these two scenarios are mutually
incompatible. I look forward to greater use of
the physical layout design for low speed
operation rather than the way things have gone so
much in our urban areas. It is possible to
achieve great things as has been shown at
Borehamwood, Herts, UK. |
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