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<br />BULB-OUTS, CHOKERS AND CURB EXTENSIONS <br /> <br />DESCRIPTION: Bulb-outs, curb bulbs, chokers, curb extensions and neckdowns are <br />synonymous for an extension of the curb into the formerly paved street area, typically for the <br />width of a parallel parking space. A low-cost design does not literally extend the curb line; rather <br />a gap remains between the former curb line and the new islands to maintain gutter flow. <br /> <br />ADVANTAGES: Bulb-outs may be installed at intersections or mid-block, on one or both sides <br />of the street. They usually do not impede or redirect traffic flow; rather they reduce the width of <br />the traveled way to the minimum required for two-way traffic. They may be used for numerous <br />purposes including: <br /> <br />. Reducing curb radii at intersections to slow turning traffic <br />. Enhancing pedestrian safety and visibility at pedestrian crossings <br />. Providing extra space for landscaping and sidewalk amenities <br />. Possibly reducing speeds by creating a sense of narrowness <br />. Creating a neighborhood gateway feature <br /> <br />Bulb-outs on one side of the street coupled with an offset centerline can be used to create <br />serpentines and chicanes. In addition, bulb-outs can be combined with small medians between <br />them to further restrict the driver's path, and to slow the speed of turning traffic, especially at <br />intersections that are angled greater than 900. <br /> <br />LIMITATIONS: The low-cost version of the curb bulb may be less expensive to construct, but <br />may be more expensive to maintain due to debris accumulating between the original curb line and <br />the new island. The narrowed travel way may present challenges to bicyclists by forcing <br />bicyclists and motorists to share the same space. Design consideration should be made for <br />bicyclists on bicycle routes. Minimum comer radii requirements for small trucks and emergency <br />vehicles may reduce the effectiveness of this option in slowing vehicles and shortening the <br />pedestrian crossing distance. Overall effects on vehicle speeds can be fairly modest. <br /> <br />ADVANTAGES: <br />. May enhance pedestrian safety <br />. May provide the opportunity for decorative hardscaping or landscaping <br />. May reduce vehicle speeds slightly <br /> <br />DISADVANTAGES: <br />. May need to consider design impacts on bicyclists and emergency vehicles <br />. May require removal of on-street parking <br /> <br />TYPICAL COSTS: Costs typically range from $20,000 to $50,000 per pair of bulbs, depending <br />upon design and extent of landscaping and/or hardscaping and drainage. Annual maintenance <br />cost is $375 each intersection. <br /> <br /> <br />City of San Leandro, Engineering and Transportation Page 17 of 23 <br />4/20/06 NEIGHBORHOOD TRAFFIC CALMING PROGRAM <br />