2010-04-14 CC Packet - Laserfiche WebLink

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Aujust 1, 2007 TRAFFIC ENGINEERING MANUAL 4_ Schoo,1 zone speed limits are not based: on the &5th percent& speed, Sperm ckee s. do) provide am accwa& refflection of the prev affing speed for average conditions and may be used as the base paint f om which speed limits can be adjusted downward for special conditions such as children crossing. The booklet "A Guide to Establishing Speed Limits in School Zones" outlines the methods to conduct the engineering and traffic iinvestigation at these sites.. This, 4bookilet is avaitablie ffrom OT—EATS and li►,as: been adopted bw Co may msio nees Order N, o- 637/00 as the off>z`wW medwd desen in MS 169.14 Smbd_52- If the study area is of a continuous curvilinear design, the area should be test driven and a ball bank survey done. Radar checks should be made at midpoints of tangents and used as a guideline for determining reammaWc vahms;. bat the coed* factor of the speed finut vti 911 be the a va a w of the sak speeds as determiieed by the bald bank suney_ Es ablishing a speed limit by this method wvirr prevent uunecessan accelerations by the driver, conserve fuel and provide safe traveling with minimum frustration encountered on winding roadways. Individual curves will still have to be checked and advisory speeds posted where nom_ 13 -6.07 Speed Zone Locations The leng h Of any section oFf'Zme set for a mtkular speed s)tmld be as tom as conibte acrd stiEli be consrsten:a with the 85th pegmatite spas.. Transition zone may be used on approaches to a city to, accompfish a gradual reduction from highway speeds to the speed posted in the city. In case the transition zones on the approach to the city are at locations where speeds fluctuate, the sections of such a zone may be as short as 1/4 mile. The change m speed; betwem two trmsiition zormes: siw l+d be ei=ter thm 5 mph. lOAA sbo uld not normal[ y be greaaer tk= 15 =b— because the change in speed would be too abnq* for driver obsservarree_ Minnesota law states that the maximum speed limit in an urban district is 30 mph. It is possible that the engineering and traffic investigation will show that the 85th percentile speed reaches a value considerably higher than 30 mph in an wban district a an area tlinms i g that a ski limit of 30 mph is teen 16w tai be reasonable and prudent_ Tlhemfore_ a reasonable and prudent screed limit should be determined and set by the Co ss isnec On a city street, municipal state -aid street or town road, the governing body may elect to decrease the speed limit to 30 mph by the procedures defined in Minnesota Statute 169.14. Subd. 5b. At locatibris where the study its extended; 5 to or throcwh city bits., t c exact point where the defiailtion of u district is met should be recorded. This is necessary )bemuse the sped limits inside the limits of the urbbaa distract may be established by the city government as described above. while the speed limits outside the urban district shall be established by the Commissioner. It is also necessary to show on the strip map. the exact location of the city limit ewer by station. and prej number- by refer ce post numbers or ltiy some other gtogram»hicads physical' feature to, prevent misisnterpremdon if he city units are changed. Other important factors in speed zone locations include the speed limit and conditions presented in front of the driver as he leaves a zone. If an in place zone is being changed or a new zone established. the roadway on each aeljrioiiniaeg side of the stm& area should be driven to detecrmcine if it is, impacted by die recommended sped limit.. The a4jo.rni ng segments should be test driven for a rength equal to 1 0 seconds of travel time at the Posted or statutory speed limit. If adjoining speed limits are affected or there are potential hazards present that would affect the driver's choice of speed, then the road authority (or the adjacent road authority) should be notified that the study am should be expanded. If t& read amthorYtly der the ad �acent road anmtlhoorrity4, refuses cxromsim of the stmd'v- this should be documented and included with the stm:dFy report w hen it is submitted to OTE -IT'S_ 13 -26 Ci'7