Chicanes create a horizontal diversion of traffic and can be gentler or more restrictive depending on the design.
Diverting the Path of Travel
Shifting a travel lane has an effect
on speeds as long as the taper is not so gradual that motorists can maintain
speeds. For traffic calming, the taper lengths may be as much as half
of what is suggested in traditional highway engineering.
Shifts in travelways can be created by shifting parking from one side
to the other (if there is only space for one side of parking) or by building
landscaped islands (islands can also effectively supplement the parking
shift).
Diversion Plus Restriction (Angled Slow Points)
Diverting the path
of travel plus restricting the lanes (as described under Chokers)
usually consists of a series of curb extensions, narrowing the street
to two narrow lanes or one lane at selected points and forcing motorists
to slow down to maneuver between them. Such treatments are intended
for use only on residential streets with low traffic volumes.
If there is no restriction (i.e., the number of lanes is maintained),
chicanes can be created on streets with higher volumes, such as collectors
or minor arterials.
