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HomeMy WebLinkAboutTraffic Memo_Update for June 6 RES COMA&F Engineering has reviewed letters submitted to the Carmel Plan Commission regarding traffic questions and concerns related to the proposed “Andrews PUD” located at 146th Street & Gray Road. The following is a follow-up to provide further information regarding traffic for this proposed development. In general, many of the comments/questions revolve around the assignment and distribution (A&D) of proposed development traffic shown in the submitted Traffic Impact Study (TIS) prepared by A&F Engineering. Typically, the assignment and distribution for a residential land use is derived using existing traffic count data, the location and type of adjacent roadways, the layout of the roadway network and the location of destination land uses (i.e., employment areas, shopping areas etc.). These variables were considered when formulating the A&D presented within the study. However, considering suggestions within the objection letters, A&F has conducted additional analyses that focused on multiple A&D scenarios. Each of these four scenarios were conducted under the following two basic assumptions. 1. No U-turns will occur at the intersection of 146th Street & Gray Road 2. All eastbound traffic entering the proposed development from 146th Street will utilize the proposed right-in/right-out access drive for the development. It was suggested that some traffic might enter from 146th Street onto Arrowwood Drive. The reasoning for this was that this intersection has an eastbound right-turn lane that might make drivers feel more comfortable entering this location. However, it should be noted that a right-turn lane along 146th Street will be required at the proposed right-in/right-out location. Furthermore, the path from 146th Street into the development drive is much more desirable than using an Arrowwood Drive which is located approximately 1100 feet west of the proposed development drive and requires drivers to travel a long and winding route through residential streets. The following table outlines the assumed A&D percentages for each scenario. Scenario Percentage To/From West 146th St. East 146th St. North Gray Rd. South Gray Rd. 1 45% 33% 12% 10% 2 35% 35% 15% 15% 3 30% 30% 20% 20% 4 25% 25% 25% 25% Note: Scenario 1 is the general A&D presented in the original TIS, while Scenario 4 represents suggested percentages by residents. The A&D percentages for each scenario shown above were applied to the proposed development AM and PM generated trip numbers (shown in Table 2 of the submitted TIS) to yield the following projected AM and PM peak hour traffic volume increases along Arrowood Drive and Wellswood Bend for each A&D scenario. Scenario AM Peak Hour PM Peak Hour Arrowwood Dr. Wellswood Bend Arrowwood Dr. Wellswood Bend 1 9 vehicles/hour 5 vehicles/hour 6 vehicles/hour 11 vehicles/hour 2 7 vehicles/hour 7 vehicles/hour 5 vehicles/hour 14 vehicles/hour 3 6 vehicles/hour 8 vehicles/hour 4 vehicles/hour 16 vehicles/hour 4 5 vehicles/hour 10 vehicles/hour 3 vehicles/hour 17 vehicles/hour Analysis of the four A&D scenarios shows an increase in traffic along Arrowwood Drive between 5 to 9 vehicles per hour during the AM peak hour and between 3 to 6 vehicles per hour during the PM peak hour. The lowest estimate (3 vehicles/hour) represents an average flow rate of approximately 1 vehicle every 20 minutes, while the highest estimate (9 vehicles/hour) represents a flow rate of 1 vehicle every 6.5 minutes (approximate). Similarly, analysis of the four A&D scenarios shows an increase in traffic along Wellswood Bend between 5 to 10 Vehicles per hour during the AM peak hour and between 11 to 17 vehicles per hour during the PM peak hour. The lowest estimate (5 vehicles/hour) represents an average flow rate of approximately 1 vehicle every 12 minutes, while the highest estimate (17 vehicles/hour) represents a flow rate of 1 vehicle every 3.5 minutes. In addition to the scenarios presented above, A&F Engineering conducted an additional trip generation analysis that compared the proposed development to what could be developed under the existing R-1 Zoning. For this analysis, it was assumed that approximately 30 single-family homes could be developed on the subject site. As was the case for the proposed townhome development, data from the ITE Trip Generation Manual was used to calculate the AM and PM peak hour generated trips from the 30 single-family homes. The following table shows the trip comparison between the proposed townhome development and what could possibly be developed on the subject site under the current R-1 Zoning. Site Development ITE Land Use Code Generated Trips AM Peak Hour PM Peak Hour Enter Exit Total Enter Exit Total 60 Townhomes 215 6 19 25 19 13 32 30 Single-Family Homes 210 6 19 25 20 12 32 Difference (Proposed – Zoning) 0 0 0 +1 -1 0 As shown in the table above, assuming the same access requirements were applied (right- in/right-out onto 146th Street and connection to Gray Oaks Court), the single-family homes allowed under the current zoning would have very similar traffic impacts as those associated with the proposed 60 townhomes.