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William Buglass <br /> Klahn Property, Town of Oregon <br /> January 5, 2004 <br /> Page 4 <br /> Exhibit C graphically illustrates the sight distance, looking north, for both cars and <br /> trucks. The top profile shows that at the present driveway location an automobile driver <br /> can detect an oncoming vehicle 1,500 feet away as it approaches the top of the crest <br /> curve. There is a critical area beyond that of approximately 180 feet where the vehicle <br /> could not be detected. However, the required sight distance for cars turning right is <br /> 1,000 feet, which well below the 1,500 feet available. <br /> Because the eye height of truck drivers is much higher, their sight line is unrestricted to <br /> an object height of 3.5 feet, which is 1 foot below the accepted height of 4.5 feet. This <br /> distance is labeled "Safety Margin"on the profiles. <br /> In order to help buffer the existing farm residence from hauling operations, it is <br /> proposed that the current driveway be relocated somewhat north. The bottom profile <br /> shows that this relocation could safely be made within 230 feet of the present driveway. <br /> Note that the analysis uses the 1' Safety Margin for both cars and trucks. <br /> It should be pointed out these sight distance calculations are very conservative <br /> because they are based on a 55 mph travel speed. The current 25 mph limit in <br /> Brooklyn begins 200 north of Douglas Drive, just 930 feet from the present driveway. <br /> So southbound traffic is reducing its speed as is passes the point of access. <br /> Furthermore, the preliminary plat of Brooklyn Sunrise Estates, 1st Addition has been <br /> approved and when this plat begins development it is likely the 25 mph posted will be <br /> moved to the north line of the new subdivision (the current Village Limits) which is 680 <br /> feet closer. <br /> Access Geometry <br /> Southbound trucks accessing the site should be given adequate opportunity to <br /> decelerate without impeding trailing vehicles. The turning radius should be large <br /> enough to allow comfortable maneuvering for long wheel bases. I recommend a <br /> standard Type B1 intersection design (150-foot taper, 200-foot deceleration lane and <br /> 60-foot entrance radius). Sight distance is not limited, so a southbound acceleration <br /> lane is not necessary. A standard 100-foot exit taper is sufficient. <br /> Depending on the location of the entrance, 3 or 4 power poles would have to be <br /> relocated in order to construct the turn lane and tapers. Additional right-of-way may <br /> also have to be conveyed. <br /> tri <br /> \P&D Klahn\traffic report.doc <br />