Agenda Packets - 2008/09/02 - Laserfiche WebLink

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Traffic Calming List of General Elements Following is a list of general traffic calming elements that may be considered for use on a local, two-lane roadway with 30 mph speed limit and concrete curb and gutter, providing access to residences and some businesses. Street Narrowing The street width can be psychological narrowed by using a white pavement edge line to indicate narrower travel lanes. Using the edge line in this manner can also play a dual role by identifying bicycle lanes or parking bays, if sufficient width exists. Without sufficient width for those purposes, signs would be needed to prohibit parking and could falsely indicate a safe bicycle lane. Speed Bump / Humps Note: Information on Speed Bumps and Speed Humps is given below since they are a common traffic calming element. However, it must be noted that Speed Bumps and Humps are not allowed on State Aid Roadways, and therefore are not appropriate for Red Oak Drive. A speed bump is a ridge constructed of bituminous. It typically rises 4 – 8 inches above the bituminous surface of the road, and is approximately 1 – 2 feet long. A speed hump is similar in height to a speed bump, but is approximately 12 – 18 feet long. Speed bumps and humps are effective at reducing vehicle speed, however they must be spaced sufficiently close to prevent vehicles from reaching higher traveling speeds between them. Speed bumps and humps do have drawbacks. They can cause maintenance difficulties for the City. They quickly become an irritant for residents who have to traverse them on a daily basis. They can also pose a danger for motorcycle and bicycle traffic if they are not sufficiently visible. They can cause damage to vehicles with low ground clearance. Choker/Bump-out A choker or bump-out narrows the width of the traveled lanes. A choker can be constructed at an intersection or at mid-block locations. This type of traffic calming provides an area for landscaping or signing to increase the psychological effect of the narrow road appearance. A choker at an intersection can increase safety for pedestrians by reducing the crossing distance. One drawback to chokers is that they increase maintenance duties of the Public Works Department. An example is that the differing width of the street will increase the difficulty and time needed for snow plowing Chicane Like the choker, the chicane narrows the street, mid-block, by constructing curb bump-outs that are staggered, thus creating a serpentine effect along the traveled lanes. The difference between this treatment and chokers is the staggered placement of bump-outs instead of two directly across from each other. The benefits and disadvantages of chicanes are similar to chokers.