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Many 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." The 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. Commonly 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. The photo shows a permanent road closure with a "T" type turnaround where the side walk has been incorporated into the turnaround area.
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 Given 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. There 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 upright position.
I 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 road closure. The approximate cost of a permanent road closure is $10-20,000. If turnaround areas are needed each one of these could cost $15,000. |
