Agenda - Public Works Committee - 11/18/2003

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PW CASE #3 CONSIDER SIGHT DIST.aAX~CE CLEAR ZONES AT INTERSECTIONS By: Steve aankowski, City Engineer Background: It is an accepted practice to require a clear sight distance zone at street intersections to enhance the safety of the intersection. A portion of the s ight distance z one i s provided b y the p ubtic fight-of-way which extends beyond the paved travel paths of vehicles. However, recommended standards for such clear zone exceed what c.an be provided within the right-of-Way. In researching the basis for establishing standards, it appears the majo? factor is providing reaction time for two converging vehicles to make speed adjustments or evasive maneuvers to avoid a collision. Reaction time at various speeds translates into distance which form sight triangle. One reference, the National Committee on Urban Transportation recommended that the unobstructed view across each comer of two local residential streets should be formed by a triangle whose sides are each 110 feet measured along the centerline distance of the approach lanes from their point of intersection. Figure A illustrates this condition. In the City of Ramsey 60-foot rights-of-way would result in a 50-foot sight triangle meeting this recommendation. The City has set backs in the single family district are consistent with this sight distance requirement. However, the increasing number of townhouse units with shorter setbacks, and Ramsey Town Center with possibly no setbacks, should cause the City to review its standards with regard to this issue. The City has requested information from other Cities as to their exper/ence and standards with this issue. Recommendation: Staff is awaiting response from other communities and will share this information at the meeting. Reviewed by: Director of Public Works Assistant Public Works Director PW: ' 11/18/03 9