02-19-2008 Agenda - Laserfiche WebLink

TO: Cass County Road Advisory Cornrnittee FROM: Keith Berndt, Cass County Engineer DATE: February 12, 2008 SUBJECT: MODERN ROUND AT CASS 17/52ND AVENUE INTERSECTION During the last Road Advisory Cornrnittee rneeting on Decernber 3, 2007 a discussion was held about the possibility of constructing a modem roundabout at the intersection of 52'd A venue and Cass 17. It was decided at that meeting that additional information would be helpful to the committee in reaching a decision. Specific concerns raised in December involved agricultural equipment, snow/ice conditions, traffic volumes, and large number of turning movements. There were also questions raised about if it would require reconstruction to accommodate future widening of Sheyenne Street and/or 52'd Avenue. I've invited Richard Lane from SRF Consulting to attend the meeting of the Road Advisory Committee scheduled for February 19. SRF has designed a number of modem roundabouts in Minnesota. I understand that the Minnesota Department of Transportation is considering a modem roundabout at the intersection of US 75 and the Minnesota extension of 52"" Avenue (Clay County 12) although I don't believe a decision has been reached. In recent months I've done considerable research on modem roundabouts. It's easy to perform a Google search and find endless information about the experiences of other communities with modern roundabouts. One good website that I'd recommend is www.roundaboutsusa.com. I'm not certain why we are not seeing modem roundabouts being constructed in North Dakota. It would appear that nearly every other state in the Country is constructing them and experiencing better success on busy roads than conventional intersections. In Montana, the legislature passed a resolution encouraging the DOT and local governments to construct more roundabouts in Montana. I've researched the specific questions that were raised during the December meeting: Large Agricultural Equipment: This has been a source of initial objection from tbe agricultural comrnunity in a number of areas. If properly designed, the roundabout can accommodate large agricultural equipment as well as semi trucks pulling multiple trailers. I found one instance on the east coast where a roundabout was designed with too small of truck apron and a very small center radius that received complaints from agricultural equipment operators. It was eventually retrofitted to accommodate the equipment. Roundabouts in Snow/Ice: Roundabouts have been constructed in many northern states with a significant reduction in accidents. I didn't fmd anything to suggest they were more accident prone in slippery conditions than conventional intersections. In some communities, one of the concerns raised was if it would be difficult for snow plow operators to clear snow. Whenever you go from a rural section without curbs to a roadway section with curbs it requires some added care 1