Traffic calming devices, such as speed humps, are widely used to help reduce vehicle speeds and improve safety in residential and commercial areas. Speed humps are parabolic vertical devices that are designed to slow traffic speeds on low volume, low speed roads. Speed humps are 3–4 inches high and 12–14 feet wide, with a ramp length of 3–6 feet, depending on the desired speed. When correctly installed, speed humps can reduce speeds to 15–20 mph. In this article, we will discuss the design and benefits of speed humps along with the importance of their placement and maintenance. We will also compare speed humps to speed tables, another traffic calming device.
Speed Hump Design Criteria
Speed humps are designed to be 3–4 inches high and 12–14 feet wide, with a ramp length of 3–6 feet, depending on the target speed. To ensure effective traffic calming, speed humps should be designed to specific criteria. Slopes should not exceed 1:10 or be less steep than 1:25, and side slopes on tapers should be no greater than 1:6. The vertical lip should also not exceed a quarter-inch in height. To ensure safety, speed humps should not be placed in front of driveways or other significant access areas. If frequent driveways make the application of a speed hump difficult, consider reducing the overall size of the speed hump, or work with local residents to find a workable solution.
Placement of Speed Humps
The placement of speed humps is critical to their effectiveness. They should be located in areas where there is a need to slow traffic speeds or reduce the possibility of speeding. Speed humps should not be placed in front of driveways or any other significant access areas. Where driveways are frequent, the size of the speed hump should be reduced or alternate solutions should be discussed with local residents to find a workable solution. Additionally, the location of a speed hump should be well-marked and clearly visible to motorists. All speed humps should also be kept at least 200 feet apart to minimize the frequency of bumps and ensure that drivers have enough time to slow down.
Speed Humps vs. Speed Tables
Speed humps and speed tables are both traffic calming techniques used to reduce speeds on low-volume, low-speed roads. While speed humps are typically three to four inches high with a ramp length of three to six feet, speed tables are larger, flatter structures that span the entire width of the road. Speed tables are usually six to eight inches high, with a length of up to twenty feet, and a gentle, flat or crowned design that allows vehicles to traverse them without experiencing any sudden jolts. Speed tables are typically used in areas with higher speed limits, stretching from 25-35 mph, as they slow traffic while allowing for smoother, more comfortable rides. The advantages of speed tables over speed humps are that they require less maintenance and are less likely to cause damage to vehicles. However, due to their size and placement requirements, they are not always the most feasible solution.
Maintenance of Speed Humps
The installation of speed humps is critical for optimal performance in traffic calming. Speed humps must be installed properly to ensure that the devices are sufficiently robust to support the weight of vehicles and withstand the effects of weather. Additionally, the speed humps must be adequately spaced and aligned with the road and adjacent property lines. Regular maintenance and repairs should also be conducted as needed.
Weather can have a major impact on the effectiveness of speed humps, so they should be inspected for damage after major storms or periods of extreme weather. Additionally, the speed humps should be periodically painted to ensure that the devices remain visible and recognizable day and night. Proper maintenance and repairs of speed humps will ensure that they remain in good working order for many years.
Speed humps are an effective traffic calming measure that can be used on low-speed roads to reduce vehicle speed. Speed humps are designed to specific heights, widths, slopes, and lip requirements that must be met in order to be effective and safe. Care must be taken when placing speed humps to ensure they are not placed in front of driveways or other access points. Speed tables are an alternative to speed humps that may be better suited for certain locations. Proper installation and regular maintenance are key to the effective use of speed humps or speed tables.
To sum up, speed humps are a safe and effective way to reduce traffic speeds on low speed roads. When designed and installed correctly, speed humps can provide the desired traffic calming effect with minimal disruption to local residents. For more information regarding speed humps and speed tables, please consult your local traffic engineering department.