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low-cost and low-impact needs. Examples of these newly implemented devices include the <br />Pilot Project Speed Lumps on Crellin Road and the Radar Speed Signs installed at various <br />locations around the City. <br /> <br />Speed humps are a very common request in traffic calming. Speed humps have two primary <br />features. Like a parking lot speed bump, a speed hump is a rise in pavement of about three <br />inches. Unlike a parking lot speed bump, speed humps are 14-feet long, so the three-inch rise <br />takes place over seven feet. This results in a very smooth rolling motion as a vehicle travels <br />over a speed hump at ideal residential speeds of 20 to 25 mph and an uncomfortable bouncing <br />motion at speeds above 30 mph. Speed bumps and humps were excluded from the Program <br />because of the delay they could cause in response time of emergency vehicles. <br /> <br />The Fire Department was concerned that while a speed hump may only slow a passenger <br />vehicle to 20 to 25 mph, the fu:e engines would need to traverse the device at a much slower <br />speed, and then try to regain that speed after crossing. The cumulative effect of several speed <br />humps was of great concern. To address this Fire Department concern, staff modified the <br />design of the speed hump to allow Fire Trucks to pass through the device without needing to <br />reduce speed. To achieve this, the basic speed hump design was modified to provide two <br />grooves that are spaced eight feet apart. The eight-foot spacing is centered over the middle of <br />the roadway and is the same dimension as the wheel spacing for fire trucks. This allows the <br />fire tracks to straddle the centerline and drive in the grooves, bypassing the lumps. To <br />differentiate between speed humps and the newly modified speed humps with grooves, we <br />refer to the latter as speed lumps. These lumps were tested by the Fire and Police Department <br />at our Operation <br />Service Center <br />prior to installation <br />on Crellin Road. <br />Upon completion <br />of testing at the <br />Operation Service <br />Center, the Fire <br />Chief was willing <br />to have the speed <br />lumps installed on <br />a City street to <br />conduct an <br />extended time <br />period review. <br /> <br /> SR:05:223 <br /> Page 3 of 9 <br /> <br /> <br />