09/14/2005 P&Z Packet - Laserfiche WebLink

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• • Mike Quigley July 21, 2005 Although not likely to be implemented, a "With Mitigation" scenario was analyzed to assess what the benefits would be if the intersections within the interchange were signalized. An analysis was also conducted to determine the benefit of converting to all -way stop control at both intersections, but this option resulted in no improvement to overall intersection LOS. Results of the operational analyses also show that the intersection of CSAH 23 / Cty. Road 14 operates at an overall failing level of service and with failing levels of service on two approaches during the PM peak period. Since no improvements are currently budgeted by Anoka County at the CSAH 23 / Cty. Road 14 intersection as noted above, the "As Is" analysis looked at what might happen if the project were to proceed with the intersection operating in its present condition. However, the "With Mitigation" scenario examined conditions with the intersection signalized assuming minimal adjustment of the roadway configuration and striping. Detailed results of both the "As Is" and "With Mitigation" operational analyses for all study area intersections are provided in Table 2. It is noted that a signal warrant analysis was conducted by Anoka County at the time turning movement counts were conducted. Anoka County found that the intersection met one of the MnMUTCD signal warrants (the peak hour warrant, for the PM peak hour). The warrant analysis was updated by RLK using 2005 traffic volumes (assuming 3.0% annual growth since 2003. The results show that again only the peak hour warrant is satisfied. Although an intersection must typically satisfy more than one of the volume warrants (8 -hour, 4 -hour, peak hour) to be considered a candidate for signalization, Anoka County has noted that improvements at the intersection will be needed relatively soon. Based on the limited amount of right -of -way available at the intersection, large -scale capacity improvements are not within their current budget, however. For the Build scenarios, a similar approach (with both "As Is" and "With Mitigation" scenarios) was taken. Discussions with Anoka County suggest that in order to accommodate site - generated traffic at the site access intersection (CSAH 23 and Street A), both right and left turn lanes be added. Anoka County's standard turn lane length is 300 feet plus 15:1 taper for 50 mph design speed roadways. Accordingly construction of a 300' southbound left turn lane and 300' northbound right turn lane are suggested, and were assumed in the analysis. It is noted that Anoka County does hope to extend the 4 -lane section of CSAH 23 northward in the future. Currently the 4 -lane section extends just beyond Marketplace Drive, the northern of the two accesses to the Super Target/Kohl's development in the northeast quadrant of the I- 35 W /CSAH 23 interchange. If and when the 4 -lane section extends to Street A, the turn lanes suggested by Anoka County to accommodate the development will need to be removed and replaced. In order to minimize the amount of roadway that will need to be replaced, it is suggested that a southbound bypass lane be considered in place of a full southbound left turn lane with speed:1 transition and 15:1 taper. Although Anoka County's past experience has shown that bypass lanes tend to violate driver expectation, that assumption holds true primarily for high speed rural roadways. As development proceeds in the area, a reduction in speed from 50 mph to 30, 35 or 40 mph may be warranted, leading to the possibility that a southbound bypass lane will be the ideal temporary solution at Street A. RLK- Kuusisto, Ltd. Page 4 of 5 Pine Glen Mixed -Use G: \23 LLC \2005 - 447- M \traffic\report\TIS memo 07- 21- 05.doc 2005 -447 -M