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should be taken to locate openings only where there is adequate sight distance. The shape and length of the median openings depends upon the width of median and the vehicle types that must be accommodated. The minimum length of median openings should be that of the projected roadway width of intersecting cross street or driveway. Desirably the length of median opening should be great enough to provide for a 50 -foot turning control radius' for left turning vehicles between inner edge of the lane adjacent to the median and the centerline of the intersecting roadway. Curbs Streets normally are designed with curbs for high utilization of available width, for control of drainage, protection of pedestrians and for delineation. The curb on the right of traffic should be about 6 inches high, usually steeply sloped. On lightly traveled residential streets with grades less than 2 percent, a lower curb that does not require modification at driveway entrances may be used. On divided streets the type of median curbs should be determined in conjunction with the median width and the type of turning movement control to be effected. Where mid-block left turning movement are permitted and the median width is under 10 feet, a well delineated flush or rounded raised median separator 2 to 4 inches high is effective in channelizing traffic, and in serving to avoid excessive travel distances and concentrations of turns at intersections. Where•traversable wider medians are appropriate they may be either flush or bordered with flat sloping lip curbs only a few inches high. On narrow and intermediate width medians, and on some wide medians, where cross median movements are undesirable or hazardous a barrier median curb should be used, usually 6 to 8 inches high and with a steep face. A high barrier curb or a central metal or high concrete barrier should be used where positive separation of opposing traffic is essential and there is no need for pedestrian crossings. Steep faced curbs 6 inches or higher adjacent to moving traffic lanes should be offset at least 1 foot and desirably 2 feet. Where there is integral curb-and-gutter construction the gutter pan width, normally 1 to 2 feet, should be used as the offset distance. Cul -deSac Turnarounds A local street open at one end only should have a special turning area at the closed end. This turning area may be of L, T or circular shape with dimensions as appropriate for the type of vehicle expected. The commonly For additional derails see GARH, pages 407 to 435. 20 Page 8 used resid Gen: Side Side acce loca be fi M. Ieg. Drh ori< res alin Roa The app: For shoe the acre all s Cer bet. poly ]oc: Ott out "Pc