pf07-053 - Laserfiche WebLink

Home

-�. Debra Bloom, P.E. City of Roseville "Weaving" Along County Road B December 3, 2007 Page 3 The applicant contends that vehicles exiting the RIRO access do not make a"weaving" maneuver to go from this access to the signalized intersection to complete their u-turn maneuver. Based on our review of the roadways physical characteristics, the likelihood of vehicles "weaving" from the RIRO access to the signalized intersection is high. The eastbound left-turn bay for the adjacent signalized intersection is approximately 50 feet from the RIRO access. The left-turn bay taper length is approximately 150 feet, thereafter. This close spacing would require a vehicle to make a relatively abrupt maneuver to access this turn lane from the RIRO access, thus, creating a"weaving" maneuver. This '`weaving" maneuver creates another unsafe situation along County Road B that is otherwise unnecessary. Proposed Outlot 81 Causal Impact The applicant has contended that the proposed development of outlot 81 will not contribute to an increase in the u-turns made along County Road B. The proposed development of outlot 81 does not directly contribute vehicles destined for outlot 81 to the u-turn movement along County Road B. However, the additional traffic generated by this proposed development will have a causal effect on the traffic attempting to access the signalized intersection of County Road B/Har Mar Northeast Access from the west or north side of the mall. Currently, vehicles making the u-turn maneuver along County Road B at the Har Mar Northeast Access are presumably from the parking area directly north of the existing Har Mar Mall. As it becomes more difficult for motorists that currently use the signalized intersection of County Road B/Har Mar Northeast Access to go west, they may shift in the future to making u-turns along County Road B as an alternative (negatively contributing to the undesirable u-turn maneuver). SRF has conducted a cursory review of the modeling analysis submitted by Wenk Associates and included the internal mall intersection immediately south of the County Road B/Har Mar Northeast Access intersection. Our review was conducted to determine if the northbound queues from the signalized intersection of the Har Mar Northeast Access would extend back into the internal mall intersection, approximately 115 feet south of County Road B. This analysis was conducted using the Synchro/SimTraffic software, with the microscopic SimTraffic software tool used to review the queuing effects. Results of the analysis indicate that under year 2009 build conditions, as presented in the Wenk Associates memorandum dated November 15, 2007, the queues from the County Road B/Har Mar Northeast Access intersection will extend back into (and block) the adjacent internal mall intersection (approximately 135 foot 95th percentile queue, with a 10 percent intersection block time). This indicates that the proposed development will have the potential to increase the u-turns occurring along County Road B due to its causal impact. In addition to the analysis discussed above, SRF reviewed another scenario with the RIRO access closed and the additional volume at the signalized intersection. Analysis results indicate that similar queues will be maintained, with the additional traffic redistributed using the signalized intersection. One may ask if these observed queues can be mitigated with timing improvements at the signalized intersection. The signal timing used in this analysis has been optimized for efficiency, taking into account other adjacent intersections that must work within the larger signal systein. Ramsey County controls the signal timing at the intersection of County