If used, pavement undulations, like any traffic engineering measure, must be used with discretion. The indiscriminate use of pavement undulations could create problems worse than those they are intended to solve. Therefore, each of the following application criteria are to be satisfied before pavement undulations will be considered:
1. The street must be a local residential street, speed limit of 25 mph, with 80 percent or more residential frontage and usage.
Reason: Local streets other than those with residential use are often planned and designed to carry both local and non-local residential, commercial, and business traffic at higher speeds than normally are desirable on a local residential street. A local street shall be as defined by the Caltrans Functional Classification System and the State of California Motor Vehicle Code.
2. There must be either an identified speeding problem (as documented by a speed survey) in which the 85th percentile speed (critical speed) is at least 33 mph, or the street must have a high incidence of speed related accidents.
Reason: Local residential streets not exhibiting an identified speeding problem should not have pavement undulations installed.
3. The street must be a through street with an uninterrupted length (eq. without a required stop or posted advisory speed curve) of 1000 to 5000 feet.
Reason: A local residential street shorter than 1000 feet generally does not generate excessive vehicular speeds. A street longer than 5000 feet generally functions as either a collector or arterial and is typically designed to carry higher volumes of traffic into a neighborhood, to be dispersed onto the local residential street system.
4. The street should have an existing (in the case of a fully built out area) or planned (in the case of an area being developed) traffic volume of less than 1,000 vehicles per day (vpd).
Reason: A local residential street with an existing or planned traffic volume of over 1,000 vpd functions as a local collector street, which should be designed to carry a larger volume of traffic at a higher speed.
5. Pavement undulations must not be placed on a street with more than two lanes of traffic, either existing or planned.
Reason: A street with more than two lanes is functioning as a collector or arterial street, which is designed to carry larger volumes of traffic at higher speeds.
6. Pavement undulations must be designed to accommodate emergency response vehicles and installation will require prior review and approval by local emergency response authorities.
Reason: Undulations on designated emergency response routes can jeopardize safety and increase response times, thus increasing the risk to life and/or property.
7. Pavement undulations must not be used on an industrial street or a street that is designated as a truck or a bus route (transit or school).
Reason: Trucks and buses, because of their longer wheelbase, experience shifting of their loads and passengers even at low speeds when crossing an undulation. Industrial streets are designed to carry trucks in order to serve businesses and industries that depend upon their services.
8. Pavement undulations must not be installed on longitudinal grades over 5 percent, curves, or locations, which are not clearly visible to motorists.
Reason: Pavement undulations in these areas can cause operational and control problems for drivers. Pavement undulations with poor visibility can result in unexpected driver behavior.
9. Pavement undulations must not be used on a street where they may cause considerable diversion of traffic from one local residential street to another local residential street.
Reason: The transfer of traffic onto another residential street can create additional traffic concerns and may lead to animosity between neighborhoods. Transferring traffic from local streets to area arterials and collectors is acceptable, but traffic capacities shall be verified.