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HomeMy WebLinkAboutTHE POINT PUD, PHASE II MASTER PLAN, PRELIMINARY PHASE PLAN - COUNTY REFERRAL - 70-88 - SUBMITTAL DOCUMENTS - ROUND 1 - TRAFFIC STUDYLA C3 W 0 Q1 w F— H R MEMORANDUM 00 C'4 To: Tom Brady, Terry Point Development Elaine Spencer, Larimer County Engineer o From: Matt Delich Date: July 5, 1988 Subject: Sight Distance Analysis I have analyzed the sight distance requirements relating to a proposed driveway access_ to Douglas Road (County Road 54) from a portion of the Terry Point Development. The design vehicle was assumed to be passenger car. The centerline profile of Douglas Road was prepared by James H. Stewart and Associates, Consulting Engineers. Criteria used was otained from the "Larimer County Access Policy," Section 4:5, Sight Distance and A Policy on Geometric Design of H i ghtway s and Streets, 1984, pgs 780-789. The prof i 1 e of Douglas Road covers the length from the west to the east property lines of Terry Point Estates. The proposed access is intended to be between Swan Lane and the east property line. From a high point near Swan Lane, Douglas. Road fal 1 s off to the east at a grade approaching five percent. The safe stopping sight distance is 350 feet. This is based upon a crossing maneuver. This distance should be increased by 25 feet c� to account for the grade in the eastbound direction. z The total safe stopping sight distance eastbound is 375 w feet and westbound is 350 feet. From field z _ sight distance problem in the � observations, there i_ no g w westbound direction. For the eastbound direction, the J closest the centerline of the driveway can be is 290 > U feet east of the centerline of Swan Lane. o_ However, the left -turn exit from a driveway or a minor street is executed at a slightly slower speed than the crossing maneuver. In this instance, the safe sight distance to the west is 490 feet plus 25 feet totalling z 515. Using this criteria, the centerline of the access a driveway should be no closer than 580 feet east of the centerline of Swan Lane. U QIt is recommended that the location of 580 feet east of the centerline of Swan Lane be used. If physical constraints prevent use of this distance, then it is recommended that the longest distance greater than 250 feet from the centerline of Swan Lane be used.