is the name given to build-outs added to a road to narrow it. There are
various configurations of chokers, but the philosophy is to narrow a
road to change its perception to drivers. When a narrowing is carried
out at an intersection the term 'bulb-out' is usually used.
least intrusive choker is a narrowing on either one or both sides of the
road which still permits two way traffic.
photo below illustrates one such choker.
have used these combined with a neighborhood entry sign or structure to
give definition to the entry point to a residential neighborhood to help
change drivers' perceptions. I have also seen individual chokers
combined with speed humps. If chokers are constructed on alternate sides
of a road it will create a winding path for traffic cutting down on the
tendency to speed on a straight road. I do not have any speed
measurements, however, to be able to quantify the speed reduction which
comes from chokers that allow two way traffic.
I have constructed as a trial chokers that only allow one way traffic with
the chokers being offset ['twisted choker' or chicane]. The photo shows
this temporary installation, which would have been replaced with curbing
if made permanent.
priority direction was signed to accord with the philosophy that drivers
need to slow down to 'negotiate' their way through with oncoming
drivers. Three of the chokers were installed on approximately one third
of a mile length of residential collector road about 26 ft wide carrying
3,000-4,500 vehicles per day. Speed studies approximately mid way
between the chokers showed very little reduction in speeds although by
observation traffic had to slow through the chicane. Contrary to what
might be expected there were no reported crashes attributable to the
chokers. The chokers remained in place for about 6 months but were
removed because residents of the road itself did not support them.
Residents cited problems with access to their property [if they lived
near a choker] and stories of irate drivers getting in to confrontations
when opposing drivers would not yield. The chokers were replaced with
'flat top' speed humps.
conclusion is that chokers should allow two way traffic and their main
usefulness is in changing the perception of a road rather than
physically changing drivers' behavior.