KERN COUNTY ROADS DEPARTMENT, 862-8850
IN THE CITY, CALL TRAFFIC ENGINEERING, 326-3724
COUNTY OF KERN RESOURCE MANAGEMENT AGENCY
ROADS DEPARTMENT: INSTALLATION OF SPEED HUMPS
The first step in the process for installing speed humps will be a public request. When a constituent makes a request for the installation of speed humps on their street, the County will:
1) Make a preliminary investigation as to whether or not the street meets the warrants for speed humps. The warrants are listed later in this report.
2) If the warrants are satisfied, determine the location of the speed hump(s) on the street utilizing the guidelines listed later in this report.
3) Issue the requesting party a standard petition form with a map showing the location of the proposed speed hump(s). The petition form will include one copy of this report to ensure that everyone has had an opportunity to review the facts surrounding the installation of speed humps.
The requesting party will be responsible for completion of the petition and presentation of this report. It will be required that 2/3 of the affected parties, as described below, and 100% of the residents within 100 feet of the speed hump installation, be in agreement with the proposed installation.
Affected parties - All property owners who (or have residents who) traverse the roadway section on a regular basis will be considered to be affected by the installation of speed humps. (This determination will be made by the County.)
It will also be required that 2/3 of the affected parties within that same area are in agreement with any future removal of the speed hump(s). This will require at least 50% of the property owners to change their mind in regards to the speed humps, and reduce the possibilities of a removal and reinstallation cycle. Speed humps must be in place for at least two years before the removal of speed humps will be considered. Once removed, it will be five years before the County will consider the re-installation of speed humps.
4) Upon receipt of the completed petition, the County will validate the signatures.
5) Once the signatures are validated, the County will construct the speed humps, place the signs and pavement markings.
Since speed humps are experimental roadway features, additions, alterations, or removals of any or all locations by the County may occur at any time.
II. SPEED HUMPS VS. SPEED BUMPS
Speed humps are different than speed bumps. Speed bumps typically have a height of 3 to 6 inches and a length in the direction of travel of 1 to 3 feet. Speed humps typically are 3 to 3.5 inches in height and 12 to 14 feet long in the direction of travel. Speed humps are generally located on residential streets where speed bumps are typically found in parking lots and private streets. The difference between speed humps and speed bumps is illustrated in the figure below.
Speed Hump vs. Speed Bump
III. ADVANTAGES AND DISADVANTAGES OF SPEED HUMPS
Speed humps have been found to have positive effects on speed reduction when used properly. Research has indicated that local residents, for the most part, feel that the features have a positive impact on the way vehicles are operated in the area. While speed humps will not really have much of an affect on the actual operations of a vehicle, drivers do tend to slow down for them.
While speed humps when properly installed do seem to have a positive effect on reducing speeds in residential neighborhoods, there are disadvantages and problems associated with them. There are traffic safety concerns surrounding the use of speed humps. There have been indications that they can cause control problems for small pickups, bicycles and motorcycles. Pedal drag (pedal hitting pavement and throwing rider) can also be a problem for bicyclists. Also, vehicles with trailers may drag their tongues while traversing speed humps. Other concerns with the use of speed humps include an increase in noise with the deceleration and acceleration of vehicles and the movement of cargo at the speed Hump, the reduction of on street parking, motorist with back problems may experience discomfort while going over the speed hump, and motorists attempting to avoid the speed humps by driving in the gutter/sidewalk area or even onto private property.
IV. WARRANTS FOR SPEED HUMPS
The following criteria need to be satisfied for speed humps to be installed:
1) The roadway shall be a local residential street, as defined by section 515 of the California Vehicle Code (CVC), with a maximum prima facie speed limit of 25 miles per hour. The road shall not be classified as an arterial or collector, as shown on the circulation element or functional classification maps.
CVC 515. A "residence district" is that portion of a highway and the property contiguous thereto, other than a business district, (a) upon one side of which highway, within a distance of a quarter of a mile, the contiguous property fronting thereon is occupied by 13 or more separate dwelling houses or business structures, or (b) upon both sides of which highway, collectively, within a distance of a quarter of a mile, the contiguous property fronting thereon is occupied by 16 or more separate dwelling houses or business structures. A residence district may be longer than one-quarter of a mile if the above ratio of separate dwelling houses or business structures to the length of the highway exists.
2) Other speed reduction techniques such as speed limit signs and enforcement have been tried and have failed to reduce speeds.
3) The roadway shall not be on an established bus route (School buses excluded).
4) The 85TH percentile speed shall be at least 37 miles per hour.
5) The traffic volumes shall not exceed 2,000 vehicles per day. Volumes exceeding 2,000 vehicles per day are likely to cause traffic to be diverted and create problems on parallel roadways.
6) The roadway shall have only one lane in each direction and have a maximum curb-to-curb width of 44 feet.
7) The minimum segment length shall be ½ of a mile (2,640 feet), with at least ¼ of a mile (1,320 feet) between stop sign controlled intersections.
8) The roadway shall have adequate street lighting to illuminate the speed humps.
9) The roadway shall have 6" to 8" non-traversable curbs on both sides of the street for 200 feet in each direction from the speed hump. Asphalt concrete dikes and roll type curbs are not acceptable.
10) Speed humps shall not be installed on any roadway where they will lead to excessive delay for emergency vehicle response times. All proposed locations will be reviewed by the Kern County Fire Department.
V. GUIDELINES FOR INSTALLATION OF SPEED HUMPS
1) Speed humps shall be placed at least 100 feet from intersections, as measured from the gutter line extension on the speed hump side of the intersection; and shall have a minimum of 200 feet of advanced sight distance for both approaches.
2) Speed humps should be spaced 200 feet to 400 feet apart. This spacing is necessary to preserve the speed profile on the street attributable to the speed humps.
3) Speed humps shall not be located over manholes, in front of mailboxes, or within 30 feet of hydrants.
4) Speed humps should be located downstream of storm drains.
5) Speed humps should be installed on property lines when possible and at least 10 feet away from driveways.
6) Basic Speed Hump Design - The basic design will follow the County's adopted standards. The speed humps will be 3 inches tall and 12 feet long, measured in the direction of vehicle travel. The 3-inch speed humps are to be placed 200 to 400 feet apart.
7) Signing and Striping - A standard 30" "SPEED HUMPS" warning sign with a "recommended speed of 10 MPH" will be installed 100 feet in advance of each speed hump, for both directions of travel. An 8-foot "BUMP" pavement legend will be painted on the pavement adjacent to the sign and chevron striping shall be placed on the speed hump.