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• Areas, under new pavement contain 2' depth sub -grade excavation, 10" depth
<br />aggregate base clas,s, 5, and 2' depth select granular borrow.
<br />• Each pay item has 5-percent added to the total quantity to account for radii and
<br />miscellaneous, areas, of sway in calculations,.
<br />In addition to the concept sketches,, Attachment B includes, Table 2 that summarizes, the cost
<br />estimate for each improvement.
<br />ROADWAY l�M�PROVE ENT' COST' ALLOCAT'l N
<br />The purpose of the roadway improvement cost allocation analysis, is to allocate future public
<br />improvement costs, related to development scenarios, identified in the Twin Lakes, redevelopment
<br />area, to the appropriate background traffic source or future development. While future
<br />developments, use up the available exces,s, capacity of the existing intersections, and roadway
<br />system, existing developments, and background traffic in the area use a percentage of its initial
<br />capacity. This initial capacity usage was taken into account when allocating future improvement
<br />costs.
<br />The following proces,s,es, and as,s,umptions, were used to conduct the analysis,-.
<br />Background Traffic Volumes
<br />Existing traffic volumes, on the adjacent roadway network were grown at a rate
<br />determined by the Metropolitan Council regional model in order to represent year 2030
<br />background traffic conditions, independent of the proposed Twin Lakes, AUAR
<br />redevelopments,. These traffic volumes, represent existing developments, in the area and
<br />other background traffic that will use the roadway under future conditions,. Background
<br />traffic was only applied to specific improvements,. Determination of which
<br />improvements, to assign background traffic to was based on the improvements, that are
<br />necessary due to existing congestion levels, (i.e., County Road D and Fairview Avenue
<br />three-lane sections, or Snelling Avenue); rather than improvements, that are required based
<br />on future development impacts,.
<br />Future Development Traffic Volumes
<br />Future traffic volumes, were developed from land use data provided in the Twin Lakes,
<br />AUAR Update. Specific land use types, were as signed a trip generation rate and
<br />distributed throughout the roadway network using the percentages, found in the AUAR.
<br />An operations, and trip distribution software package (Traffix for Windows,) was used to
<br />determine the trip allocation percentages, by intersection. The Traffix model results,
<br />provide a detailed breakdown of percent trips, at a given intersection based on the trip
<br />source (existing trips, at an intersection or a particular developments, trips, passing through
<br />the same intersection).
<br />City of Roseville Twin Lakes AUAR Area
<br />February 2008, Infrastructure Improvements
<br />Page 5
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