people do not consider road closures to be traffic calming measures at
all because they re-direct traffic to other routes. It is true that road
closures are far more extreme measures than speed humps and chokers
which still allow through traffic to use the roads on which they are
installed. The difficulties associated with road closures are far
greater than less restrictive measures, not least because of the controversy
which they cause. None the less there are places that lend themselves to
road closures and I think it is appropriate to keep the possibility of
road closures in the traffic calming "arsenal."
most restrictive closures completely close a road. Less restrictive (and
not self-enforcing) are partial road closures which prohibit traffic in
one direction only, and forced turn channelizations which are partial
road closures which require traffic to make a right turn onto an
intersecting street. The best place to consider road closures is at an
intersection to prohibit entering and exiting traffic. One problem that
has to be faced with road closures is the need to create a turning area
for vehicles. If a public road is closed at some point other than an
intersection, turning areas will be needed from two directions.
accepted standards for turning areas, as found in the American
Association of State Highway and Transportation Officials (AASHTO)
standards, are 60 feet diameter culs-de-sac, 60 feet "T"
turnarounds and 50 feet hammerhead configurations. A common problem is
that rights of way for older areas are below 60 feet meaning that
private property would have to be acquired for a standard turning area.
photo shows a permanent road closure with a "T" type
turnaround where the side walk has been incorporated into the turnaround
If no turnaround area is provided larger
vehicles will be forced to back possibly for long distances with
consequent danger and liability. Emergency services will usually prefer
a cul-de-sac turnaround which enables them to turn more quickly.
A common objection to road closures is
that they delay and confuse emergency services. Some closures have
attempted to address this by providing gates at the closure which can be
opened by emergency service vehicles by garage door opener devices.
The below photo shows one such gate.
A more simple and less expensive alternative would be to install top locking bollards
the controversial nature of road closures one approach is to undertake a
trial closure on a temporary basis. The closure can then be made
permanent if it is found to be successful.
is also public pressure for road closures from a crime prevention rather
than purely traffic standpoint. Again the issue of emergency access can
arise and the next photo shows a crime prevention road closure installed
on a temporary basis which is accessible to the emergency services and
police by the use of a number of flexible stake or highway delineators
which can be driven over and are spring loaded to come back into an
have found the maintenance requirements on these to be extensive but
they are working and do not seem to be widely misused by the public. My
next step may be to design something similar to this into a permanent
approximate cost of a permanent road closure is $10-20,000. If
turnaround areas are needed each one of these could cost $15,000.