1982-02-18_GENERAL DOCUMENTS - M1981302

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Staff Recommendation Docket #SU-81-20 November 13, 1981 Page Seven TDA, the applicants' traffic consultants , suggest reopening the northerly access point from Marshall Road to Highway 93. This would mean that trucks would enter the highway approximately 700 feet north of the mobile home park entrance, which would serve to elimiate concerns about proximity to the park. Unfortunately, neither County Public Works north the State Highway Dept. supports reopening this access due to its location on both a horizontal and a vertical curve andresult in inadequate sight distances for slow-moving trucks. For noise reasons, traffic reasons and due to potential conflicts with non-vehicular recreational traffic on Old Marshall Road, staff does not feel that an acceptable proposal for a south haul route exists and that the south haul route should be eliminated. The applicants have responded that the mobile home park is already impacted by traffic noise from Highway 93 and that additional noise impacts from haul traffic should be minimal . Staff notes the following differences between existing highway impacts and proposed haul road impacts: 1) The minimum distance from the highway centerline to the nearest mobile home is about 200 ft. The centerline of Marshall Road is only 80 ft. , or less than half the distance to the highway. 2) Traffic moving by on the highway at steady speeds does not have the impact of accelerating, decelerating and stopping trucks. As an example, one of the recognized methods of protecting traffic noise, the HUD method, assigns an impact multiplier of 5 if there is a traffic signal or stop sign within 800 feet of the area receiving the noise. 3) Additional impacts will also be created by acceleration and deceleration of trucks entering and leaving the highway. The sustained grade of Highway 93 is 2.8% with maximum spot grades of 4.9%. This will also add to the noise of the addi- tional trucks. The HUD method uses an impact multiplier factor of 1.4 for 34% grades and a factor of 1. 7 for 5-6% grades. 4) The traffic studies submitted have primarily used average figures, including average allocations of numbers of trucks per day to the north and south haul roads. In reality, the applicants admit that the south haul road would only be used if contracts for materials or construction were acquired in the south Boulder area. If large construction contracts were received for the south area, it is quite likely that maximum production hauling could occur on the south haul road for the duration of such projects. Thismeans that haul traffic impacts could be con- siderably higher than the maximum of 23 loads per day projected in the transportation studies. 5) Due to the close proximity of Marshall Road to the mobile homes, the public right-of-way and private ownership of the 70' -wide strip of land between the roadbed and the mobile homes and the necessary height of any effective noise barriers, it would be very difficult or impossible to reduce excessive noise levels to an acceptable level . In any case, no mitigation measures have been proposed by the applicant.