Cul-de-sac Design
Cul-de-sac Design
(OP)
Our city regulation require the lenght of a cul-de-sac to be no more then 1200 ft., this I find is a standard in the country. Many residents prefer to live on cul-de-sacs so this creates a conflict, a balance that is tough to manage!!! I would have thought there was a sound engineering or technical public safety reason but I have been unable to find it??? Some of the thing I thought may be the reason were lenght of fire hose carried by an avg. fire company, water pressure of a hydrant vs. lenght to a house, etc... All these and others I researched have too many other variables and really could not be the reason for this 1200 ft max. To better explain it to my residents, does anyone have any input, sources to research or the answer to this requirement????





RE: Cul-de-sac Design
RE: Cul-de-sac Design
RE: Cul-de-sac Design
Given the available power of the current generation of cars, 1500 ft might actually be too long.
TTFN
RE: Cul-de-sac Design
Not in the RSIS, but governed by other code is a requirement that a school bus may not back up without an adult behind the bus to guide the driver. Since most school buses have no second party on board, and there is always a chance that a car will be parked on both sides of the cul, we (planning Board) require a 55 foot radius paved cul. Since the RSIS permits less, we will permit the lesser radius , with the proviso that all sales maps state promanantly that school buses will not be permitted down that cul de sac. The developer will often volunteer a 55 foot radius.
Trafficpro
RE: Cul-de-sac Design
Not all planning boards require a 55 foot paved cul de sac as suggested. A muncipal ordiance prohibiting parking may reduce the concern. The minimum 40 ft. radius as required in the RSIS has been the standard in many towns for a long time and works quite well.However that is an issue between the developer and the board.
RE: Cul-de-sac Design
KRS Services
www.krs-services.com
RE: Cul-de-sac Design
1. With much success, we've built cul-de-sac roads of several thousand feet with one caveat, it must be privately owned and maintained by the development's HOA.
2. Emergency access is certainly an issue, so we often incorporate loops along the course of the cul-de-sac, using the open space for tree planting and other visual effect. This provides a bypass in the event of an accident and some variation from repetition of house after house after house.
3. To slow down traffic and add visual feature, we incorporate traffic circles.
4. Looping of waterlines is a must to ensure access to water for firefighting purposes and supply in case of a break.
5. One thing we are doing in a current project is building a paved alley, if you want to call it that, from one cul-de-sac bulb to another. We put about a 25' separation between two lots to accomodate this paved strip. It is blocked for regular traffic, but accessible by emergency and maintenance vehicles. Local residents would have to unlatch a gate and jump the curb to gain access, making it unfeasible for normal use.
6. For publicly owned cul-de-sac streets, we have similar limitations to those named by others with some extension allowed due to terrain or other site limitations such as triangulated land parcels, major stream or wetland crossings, etc.
Hope this is helpful.
Jeff Foster, PE
CE Group, Inc.
Apex, NC
RE: Cul-de-sac Design
RE: Cul-de-sac Design
TrafficPro
RE: Cul-de-sac Design
RE: Cul-de-sac Design
Once the roadway is located make sure the radii are sufficient going in and out. Sometimes a central landscape island is provided to get larger turn radii. Thjis is acceptable ONLY in privately owned developments, as the island need uipkeep.
RE: Cul-de-sac Design
Once the roadway is located make sure the radii are sufficient going in and out. Sometimes a central landscape island is provided to get larger turn radii. This is acceptable ONLY in privately owned developments, as the island need upkeep.