Engineering Division - Traffic Section - Traffic Calming
PAVEMENT UNDULATIONS POLICY & PROCEDURES
ATTACHEMENT IV
INSTALLATION DESIGN CRITERIA
1. Pavement undulations will only be considered for installation on streets that are constructed to County Standards with a pavement that is determined to have a reasonable (5 year minimum) life expectancy and that is not scheduled for pavement rehabilitation.
2. Pavement undulations are vertical speed control measures consisting of speed humps or speed tables as described in the Federal Highway Administration/Institute of Transportation Engineers' informational report Traffic Calming: State of the Practice, August 1999 edition.
3. Pavement delineation for pavement undulations will be in accordance with the Federal Highway Administration's Manual on Uniform Traffic Control Devices (MUTCD), December 2000 Edition, unless otherwise approved by the Public Works Director.
4. Undulation types shall be Speed Humps or Speed Tables: The length of Speed Humps vary 12 feet from the beginning of rise from the pavement surface to return to the pavement surface. Speed Tables typically have 10 feet of flat surface on top that is long enough for the entire wheelbase of a passenger car to rest on.
5. Pavement undulation profiles should be 3 inches in height at the highest point and should taper along a circular arc at each vertical transition, unless otherwise approved by the Public Works Director.
6. Pavement undulations should be spaced approximately 200 to 500 feet apart to obtain maximum effectiveness. This spacing will tend to reduce acceleration and deceleration maneuvers by motorists between undulations. The minimum space between pavement undulations shall be 200 feet.
7. Pavement undulations should be tapered from zero elevation near the lip of gutter or edge stripe to the full undulation height approximately 1 to 3 feet into the traffic lane. Pavement undulations located at pedestrian crossing locations shall conform to height differential requirements for crosswalk surfaces. Where rolled curb is used, it may be necessary to place traffic bollards adjacent to the sidewalk to prevent motorists from driving on it to bypass the undulations. These traffic bollards should have high visibility during both day and night time conditions.
8. An appropriate advance warning sign with 15 mph advisory speed sign should be installed between 50 and 250 feet in advance of the first in a series of pavement undulations.
9. An appropriate warning sign should be installed at the point of undulation.
10. Pavement undulations are not to be placed over utility access covers.
11. The edge of the pavement undulation should be at least 5 feet from the edge of a driveway.
12. Wherever possible, pavement undulations should be placed at property lines rather than mid-lot.
13. Where possible, pavement undulations should be placed adjacent to street lighting.
14. Pavement undulations should be placed between 100 and 200 feet away from any stop intersection or sharp curve, and should be visible for approximately 200 feet in either direction.