Agenda - Council - 07/09/1996 - Laserfiche WebLink

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Stop Signs A stop sign is one of our most valuable and effective traffic control devices... when used at the right place and under the right conditions. It seems so easy and inexpensive we can discourage unwanted traffic from using a street and control the speeds of the remaining traffic by simply installing a stop sign. At least that is what cities and counties are told daily by concerned residents. But does it really work, or is it just a symbol that really does not deter traffic? Or worse yet, does the stop sign create larger traffic problems? Stop signs have been installed and studied often so many of their benefits and detriments can be predicted for a particular location. A stop sign is one of our most valuable and effective traffic control devices... when used at the right place and under the right con- ditions. It can also pollution in urban areas are generally at inter- sections with high volumes of idling traffic. Research has shown that 1,000 automobiles decelerating to a stop from 35 mph and then accelerating back again will increase carbon monoxide emission by 24 pounds, hydrocar- bons by 1.7 pounds and nitrogen oxide by 1.9 pounds. These quantities may be slightly high for new cars, but they represent the situation where only single cars are stopping. The stated cost of a stop sign may be mea- sured by its cost of approximately $50 to install. The true cost should reflect vehicle impacts. A single stop sign installed on a 25 mph street in a Wisconsin city was calculated by university engineers to increase annual fuel costs by 60,000 gallons or about $75,000 per year. Installing a stop sign or series of stop signs may divert some traffic from that street. create a dangerous Unfortunately, that traffic be diverted to may ..,-,,,~ :-.: ~ZV;':',;':~'~:'~., ...' situation and another street where ultimately the same .~., .-~-~ .' .d :,,- ~: ' ,'::' '1 . ' L~>. . , ~'-"'-~"-;'~:'.':.:':" ......... : ........ d~mm]sh the effec- demand for a stop sign may be made. Traffic tiveness of other signs when improperly used. be diverted to secondary streets less able may It is often assumed that installing a stop sign to safely carry the traffic volume. Studies have will slow traffic along a stretch of road. Unfor- not been able to document any long term tunately, overall speed may actually increase, reduction in traffic caused by the simple A number of drivers are so,me what irritated installation of a stop sign. by th,e, installation of these speed control stop A final conceTM over installing a stop sign at signs' and develop a tendency to make up for an intersection with a low volume traffic on lost time by over accelerating or by traveling the cross street, or at a mid-block location, has at higher speeds between signs, to do with the effectiveness of the sign itself A Study in San Francisco showed that and its impact on other stop signs. A Michigan speeds only 100 feet past the stop sign were study showed that approximately half of the within 3 mph of the top level of speeds· This motorists made a rolling stop at the stop signs study also showed that speeds at a mid-block on local streets, and one-quarter of traffic did location, two blocks from any stop sign were not stop at all. Observations throughout the St. 3-5 rnph higher with a stop sign than after the Paul and Minneapolis metropolitan area have stop signs had been removed. The only actual also shown a high volume of rolling stops at reduction in speed appears to be within a few intersections where cross traffic conflicts are hundred feet of the stop sign itself· not anticipated. Accidents do occur with stop Residents near the stop sign, while seeing signs and accident rates can increase after lowe~ speeds, are faced with other new prob- installation of stop signs. lems. Decelerating and accelerating vehicles When stop signs are requested to control make more noise than those passing at a con- speed or discourage traffic, the best approach stant speed. Commercial vehicles, diesel may be to ana- engine vehicles, and those with exhaust prob- lyze the problem ~o~itio,,~t ~ and situation in iuformatio~l co~tact ; lems or modifications add significantly to the ....... Gte,, Van Wormer, noise level when accelerating, aetan ano ioof< , · Transtortation ' '.~.~ ' There is also an air quality element associ- for alternahve o , t,, ,t "a, ~ ep r ~e~ tvt ~ager. :. ated with vehicle stops. Hot spots for air solutions. ~ ..'.?Z~?