2009-02-25 CC Packet - Laserfiche WebLink

Home Browse Search

is based on standard average crash rates for certain intersection control types. The proposed interchange configuration is designed such that certain m,yor conflicting movements at the ramp intersections will be reduced or eliminated. Therefore, the actual crash rate for the traffic signal control intersection type could be reduced, thereby reducing the projected crashes per year to reflect the safety improvements associated with the interchange re-configuration. Warrants Analysis A warrants analysis was conducted by applying the applicable warrants for multi-way stop applications and traffic signal control as outlined in the May 2005 Minnesota Manual on Uniform Traffic Control Devices (Mn/MUTCD). There are no nationally accepted warrants for the installation of roundabouts because roundabouts are both a roadway element and a traffic control device. Roadways are typically designed to accommodate traffic yolumes for 20 years into the future and traffic control devices are typically installed when warranted. Traffic signal control and all-way stop control do have warrants that are recognized at the national level and some agencies, including Mn/DOT, have adopted these warrants for roundabouts. Tables 4, 5 and 6 provide a summary of the results. The 70% factor was applied due to the high speed of the CSAH 14 mainline (45 miles per hour). In addition, right turning vehicles for the minor approaches were either eliminated or reduced for each warrants analysis based on procedures documented in the 2000 Highway Capacity Manual. For the forecasted volumes, the sth-highest hour was estimated based on the a.m. peak hour and p.m. peak hour volume forecasts. If the warrant criteria are met for Warrant I using the Sth-highest hour, then it is assumed the warrant is met for eight hours. Therefore, the results of the analysis indicate only three hours met (a.m. peak hour, p.m. peak hour, Sth-highest hour). Details of the warrants analysis can be found in Appendix B. Table 4 Warrants Analysis Results (Existing Year 2008 VolumeslYear 2030 Forecasted Volumes) CSAH 14JI-35E Northbound Ramos Hours Existing Year 2030 Mn/MUTCD Warrant Year 2008 Volumes Forecasted Volumes Required Hours Met Warrant Mel Hours Met Warrant Met Multi.way Stop Applications' a 7 No 3 Yes *t Warrant lA: Minimum Vehicular Volume a 7 No 3 Yes ... Warrant 1 B: Interruption of Conlinuous Traffic a 13 Ves 3 Yes ** Warrant 1C: Combination of Warrants a N/A -- N/A - Warrant 2: Four-hour Vehicular Volume 4 11 Ves 3 Yes ...... Warrant 3B: Peak Hour 1 9 Ves 3 Yes . The eXisting all-way slop was installed to improve the safety of the intersection as recommended in the T raffle Safety Study _ CSAH 14 (Main SI.) Corridor near 1.35E (Anoka County Highway Department, November 2001). .. Based on estimating the a"-highest hour (only 3 hours required). ~CONSl!LlING GROUP, INC. -9- January 30, 2009 26