C . Speed Humps / Speed Tables
Speed humps are used to reduce traffic speed by having a gradual mountable slope which would present a minimal discomfort for slower traffic , but would be uncomfortable for drivers at higher speeds . Speed humps are generally installed on local streets with high pedestrian and bicycle traffic , such as adjacent to schools and Main Streets . Bicyclists can ride over speed humps safely ( Figures 7.9.6 )
Speed tables are similar to raised crosswalks but are used for reducing vehicular speeds only . A raised speed table can be constructed similarly to raised crosswalks but will not include signing and marking for pedestrian crossings ( Figures 7.9.7 ).
Design Criteria :
• Speeds humps are located on streets that have more than 300 and less than 3,000 trips a day .
• Reduce speed between speed humps to 15-20 mph .
• Install street signage indicating speed hump approach a minimum of 100 feet in advance .
• Install speed humps 300 to 400 feet apart on a road .
• Speed humps to be 200 to 300 feet from intersections .
• Add speed limit of 15 mph over speed hump .
• Install pavement marking , including indicating speed hump ahead , white striping and white reflectors .
• Refer to Figures 7.9.8 and 7.9.9 for typical speed hump detail and plan .
• Maintain minimum travel lane requirements per City of Arlington Design Criteria Manual and the Thoroughfare Development Plan .
• A speed table is a reverse curve with a level area in the middle and then another reverse curve . The level area in the middle is approximately the width of a motor vehicle wheel base .
• Refer to Figure 7.9.10 and 7.9.11 for a typical raised speed table detail and plan .
• Evaluate storm drainage design and driveway locations prior to installation of speed humps .
Figure 7.9.6 . Perspective sketch of speed hump .
Figure 7.9.7 . Perspective sketch of speed table .
Chapter 7 : Design Guidelines | 7-79