Chicanes
6.4.1 Chicane designs vary considerably but most
fall into two broad categories:
• single-lane working, consisting of staggered build-
outs, narrowing the road so that traffic from one
direction has to give way to opposing traffic
• two-way working, using build-outs to provide
deflection, but with lanes separated by road
markings or a central island.
6.4.2 A single-lane working chicane allows traffic
in both directions, but there is only room for one
vehicle to pass through at a time. Generally a priority
is given to one direction, so that the possibility of
vehicle conflicts is minimised. Priority should be given
to vehicles leaving a traffic-calmed area, so that the
speed of vehicles entering is reduced.
6.4.3 Two-way working chicanes take up more
carriageway space than other chicanes, as they allow
two vehicles to pass in opposite directions at the same
time. Where chicanes do not have a central divider,
vehicles can encroach into the opposing traffic lane,
and this may result in less speed reduction being
achieved, and/or safety being compromised.
6.4.4 Chicanes have been used successfully
in traffic calming schemes. However, in some
instances the features have been removed because
of complaints from residents, emergency services,
or bus operators. Consultation prior to installation
of horizontal deflections is a necessary part of the
design process (see Section 2.4). Besides the groups
mentioned, consultation should include haulage
associations, particularly if an abnormal load route is
involved, and farmers in rural areas.