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Speed Humps. Speed humps (also called undulations) reduce speeds on residential streets by <br /> compelling motorists to slow to residential speed limits when approaching the hump. Speed <br /> humps are 14' to 22' in length and are approximately 3" high. They are most effectively used in <br /> clusters of three to five, and are generally installed at intervals ranging from ' to ' apart. <br /> Speed humps are not to be confused with speed bumps. Speed bumps much more abrupt, usually <br /> less than 3' in length, and are used in parking lots and private drives. Speed bumps are not used <br /> on public streets. <br /> The 14' speed hump design, when used in a series, will reduce the average vehicle speed to <br /> approximately 25 mph. The 22' design will reduce the average speed to approximately 35 mph. <br /> This hump extends laterally over the width of the roadway sloping to the existing grade within a <br /> foot or two of the gutter. This design allows bicyclists to weave around the hump near the curb <br /> to avoid having to cross the hump. <br /> While primarily used for speed reductions, speed humps also tend to reduce traffic volumes on <br /> streets where they are employed as motorists choose alternate routes to avoid them. <br /> Raised Crosswalks The purpose of raised crosswalks is to slow vehicles entering a given area <br /> from an adjacent street. These features are also intended to identify a "threshold" or entry and <br /> exit point for a neighborhood and can be used to highlight the importance of a pedestrian or <br /> bicycle dominated intersection. <br /> A raised crosswalk is designed to maintain the same grade as the approaching sidewalk. The <br /> width of the approaching sidewalk is also maintained (typically 5'). With new construction, the <br /> area of transition from the grade of the threshold walkway and the adjacent street is to <br /> feet maintaining a slope of %. (THIS SENTENCE IS NOT CLEAR - WHAT'S IT MEAN). In <br /> retrofit situations the slope and grade will vary depending on existing conditions. <br /> A landscaped median or curb extension may be used in combination with the raised crosswalk to <br /> further additional vehicle speed reductions. Raised crosswalks are generally only used with <br /> some form of intersection control such as a stop sign or traffic signal.. The speed of vehicles <br /> leaving an intersection with a raised crosswalk is not affected due to the presence of the <br /> intersection control <br /> Curb Extensions Curb extensions, also called chokers or bulb -outs, narrow the street by <br /> widening the sidewalks or landscaped parking strip. They are used to make pedestrian crossings <br /> shorter, and therefore easier and safer. They also narrow the area of pavement and travel lane <br /> widths providing a visual cue to the driver that caution is necessary. Where curb extensions are <br /> constructed by widening the landscaped parking strip, they can have a positive effect on visual <br /> appearance of a neighborhood. <br /> Curb extensions can be used at intersections to create a street gateway or threshold effect, <br /> visually announcing an entrance to a residential neighborhood. At intersections, curb extensions <br /> are normally used in conjunction with a stop sign or traffic signal; in these locations when curb <br /> extensions are designed with a raised crosswalk and/or a landscaped median, the effect on street <br />