5.1. SR 03-12-1996 - Laserfiche WebLink

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S.~._TATE OF MINNESOTA DEPARTMENT OF TRANSPORTATION P.O. Box 370 3725 12th Street North St. Cloud, MN 56303 Office Telephone: (612) 255-4181 Fax: (612) 255-3257 March 5, 1996 Scott Brabec 13822 211th Ave. N.W. Elk River, MN 55330 RE: Elk River Comprehensive Transportation Plan Dear Mr. Brabec: Thank you for driving up to St. Cloud to meet with me regarding the Elk River Comprehensive Transportation Plan. This letter will serve as a summary of what I believe to have been some of the key points of our discussion. In some parts of the letter I may have added information subsequent to our conversation to help clarify my thoughts. One question I had provided feedback on was the ability of the traffic assignment model used by the city to show trip reduction on routes para/lel to the proposed east-west corridor. My understanding of the traffic forecasting model used for the Elk River study is that it was an "Ail or Nothing" assignment model. An "All or Nothing" model will assign trips to the route which has the shortest trip time, regardless of th.e, fact that the number of trips assigned to the route may eventually' exceed the route s capacity and ultimately make it a less desirable route. An alternate method would be to do a UCapacity Restrained" assignment model. A "Capacity Restrained" process is an iterative process which would adjust the travel speeds on route segments as they become congested. This process has the effect of diverting trips off of heavily used routes and on to lesser used routes. Since the model used in the study is an "All or Nothing" model, the trips being diverted to new or lesser used routes may be understated since an "All or Nothing" model focuSses on where trips want to go rather than their desire to avoid congestion. To get an understanding of how these lesser used elements of the transportation system might work, the parallel routes also have to be considered with regard to how much congestion they are