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<br />CHICANES <br /> <br />DESCRIPTION: A serpentine street or chicane is an artificially created, curving, two-way street <br />on a naturally straight road section. The curvilinear alignment requires additional maneuvering <br />and breaks up long straight sight lines for motorists. <br /> <br />APPLICATION: The curves can be created by offset centerline striping, a series of bulb-outs or <br />parking areas installed on alternating sides of the street, or by varying the size or shape of a series <br />of median islands. The length of the curve and the amount of side-to-side offset can be varied to <br />obtain more or less reductions in speed. They may be used at both midblock and at intersections. <br />In addition to the forced speed reduction, a serpentine alignment that is created by landscaped <br />islands gives the appearance that a street may not be a convenient shortcut. Chicanes may reduce <br />traffic volumes depending upon the traffic circulation and the availability of alternate routes. <br />Travel lanes usually need to be narrowed in order to further reduce the ability of drivers to <br />straighten the curves. <br /> <br />LIMITATIONS: If raised islands do not force the lane offsets, many drivers will easily <br />"straighten the curves" by not staying in the proper lane in the transition area, thus reducing the <br />effectiveness of this measure. Any chicane must be designed to permit travel by emergency <br />equipment. Because the designs are so diverse, it is not possible to generally describe the added <br />delays to emergency equipment. Chicanes tend to be ineffective on roadways with more than two <br />lanes due to the tendency to cut a straight path. <br /> <br />ADVANTAGES: <br />. Provides for landscape opportunities <br />. Minimal impact on emergency vehicles <br /> <br />DISADV ANT AGES: <br />. Relatively expensive <br />. Needs to be combined with narrowing lanes <br />. May require on-street parking removal <br /> <br />TYPICAL COSTS: Costs are highly dependent upon the design and may range from $15,000 to $30,000. <br />The annual maintenance cost is approximately $250 per block. <br /> <br /> <br /> <br />~ <br /> <br />r <br />?c( <br /> <br />----" <br /> <br />City of San Leandro, Engineering and Transportation Page 13 of 23 <br />4/20/06 NEIGHBORHOOD TRAFFIC CALMING PROGRAM <br />