2009-02-25 CC Packet - Laserfiche WebLink

Home Browse Search

VI. Other Considerations Right-of- Wav Considerations The comparison of right-of-way impacts between a conventional intersection and a roundabout depends primarily on the design vehicle and required geometrics. If the design is to accommodate large trucks, a roundabout generally requires more right-of-way at the intersection. Generally, a trade-off exists with a conventional intersection requiring less right-of-way at the node and more right-of-way for the approaching roadways to accommodate turn-lanes when compared to a roundabout. Based on the revised interchange configuration, additional right-of- way is already required to accommodate the loops and the additional distance between the ramp intersections. In order to determine the actual right-of-way impacts as a result of installing roundabouts, the size of the roundabouts would need to be determined to see if additional right- of-way would be required. T ransportatien Svstem Considerations As previously noted, roundabout control shall not be considered feasible at locations where the ADT exceeds 20,000 based on the Anoka County interchange/roundabout/intersection decision process developed for planning purposes. For existing year 2008 volumes, roundabout control could be feasible at the CSAH 14/I-35E Southbound ramps and the CSAH 14/21" Avenue intersections; however, roundabout control would not be feasible under year 2030 forecasted volurne conditions. Therefore, operation of the CSAH 14/I-35E ramp intersections as a system with the closely spaced adjacent intersections along CSAH 14 is recommended to minimize the impacts to the transportation system along the CSAH 14 corridor with respect to the recommended interchange configuration (see "Future Conditions"). Installing traffic signal control at the reconstructed CSAH 14/I-35E ramp intersections and the reconstructed CSAH 14/21" Avenue intersection will allow for the intersections to operate as a coordinated system within the interchange area. This will provide coordination for heavy movements during the peak hours which reduces the vehicular delay and controls the queuing interaction among the intersections along CSAH 14. Additionally, providing traffic signal control at the CSAH 14/I-35E ramp intersections allows for control of the ramp queues in order to minimize the possibility that queues will spill back onto the freeway. VII. Recommended Alternative The following conclusions are provided for this intersection control evaluation for the 1- 3SE/CSAH 14 interchange reconstruction project in Anoka County, Minnesota: . Crash Analysis Roundabout control and side-street stop control are anticipated to have the lowest number of crashes in year 2030 whereas all-way stop control and traffic signal control are anticipated to have the highest. . Warrants Analysis Traffic signal control is warranted at the reconstructed CSAH 141l-35E ramp intersections by satisfying the requirements of Warrants 1B, 2 and 3B under existing year ~CONSt.!'L"'INC GROUP, INC. - 16 - January 30, 2009 33