Boone County Public Works Department

Traffic Safety Manual - Boone County, Missouri

 

6.0    NON-STANDARD TRAFFIC CONTROL DEVICES

Boone County will avoid the use of non-standard and unproven traffic control devices such as Children at Play signs or Speed Bumps. Engineering assistance may be provided for neighbors that are interested in various traffic calming options.

 

6.1 Children at Play Signs

The Missouri Department of Transportation does not recognize the use of the SLOW – CHILDREN AT PLAY or similar messages sign. Parental concern for the safety of children in the street near home and a misplaced but wide-spread public faith in traffic signs to provide protection often prompt the request for these types of signs.

 

No factual evidence has been presented to document the sign’s success in reducing pedestrian accidents, vehicle operating speeds, or legal liability. Studies have shown that many types of signs attempting to warn of normal conditions in residential areas have failed to achieve the desired safety benefits. If signs encourage parents and children to believe they have an added degree of protection, which the signs do not and cannot provide, a great disservice results. Children should not be encouraged to play within the street travel ways. This sign has long been rejected since it is a direct and open suggestion that this behavior is acceptable. Therefore, the County will not promote or provide the SLOW-CHILDREN AT PLAY sign.

6.2   Traffic Calming

Traffic Calming is the application of techniques at a specific location that result in a reduction in vehicular speeds, traffic volumes, traffic noise, and accidents. The techniques may include educational programs, neighborhood speed watch programs, improvements in traffic signing, increased enforcement, reduction of speed limits (see Section 3.4), or physical alterations to the roadway to change driving patterns. The support of the residents where traffic calming is being considered is critical to the success of any neighborhood traffic management program and they must therefore be an integral part of any process.

 

A traffic calming project shall be designed and sealed by an engineer register in the State of Missouri . The traffic calming project shall include a traffic study. The design shall be reviewed and approved by the County. For existing neighborhoods, the design and construction of the project shall be at the expense of the neighborhood. For new subdivisions, the design and construction of the project shall be at the expense of the developer. The objectives of traffic calming can frequently be met without physical changes to a roadway. The least intrusive solution is always the preferred one from a traffic engineering perspective. The County Highway Administrator will not endorse the use of speed bumps, unwarranted stop signs, or arbitrary lowering of speed limits. The traffic calming devices shall comply with Traffic Calming: State of Practice , developed by the Federal Highway Administration (August 1999). The following are most commonly applied devices.

1.   Speed Humps

Speed humps are raised sections of the roadway constructed to reduce vehicular speeds. Similar to a speed bump, the speed hump is wider and has a more sloping side taper. The physical impact on passing vehicles is less severe at slow speeds than at higher speeds.

 

2.   Traffic Circles

A traffic circle is a large circular area in the middle of an intersection constructed to control the right-of-way of vehicles. The circle is used to decrease vehicular speeds on a residential street and may decrease traffic volume as well. Traffic approaching the intersection must drive around the circle and yield to those cars that have already entered the circle.

 

3.   Chicanes

A chicane is created by staggered curb extensions that are placed on both sides of the street. These curb extensions alternate on the street and force motorists to substantially decrease their speed when driving around them. In addition, depending on the design, motorists may have to yield to oncoming traffic, when the curb extension is designed to allow only enough space for one car to pass at a time. The extensions, often landscaped with bushes and trees, decrease the driver's line of sight, and therefore, decrease the speed with which the motorist can drive with comfort.

 

4.  Realigned Intersections

A realigned intersection is created by changes in alignment at T-intersections with straight approaches into curving streets that meet at right angles. A former straight through movement on the top of the T intersections becomes a turning movement.

 

5.  Center Island Narrowing

Center Island Narrowing is created by constructing raised islands along the center line of a street. The island narrows the travel lane at that location decreasing the speed that the motorist may drive with comfort.

 

6.  Textured Pavement

A textured pavement is a roadway surface paved with brick, concreted pavers, stamped asphalt, or other surface material that produces constant small changes in vertical alignment.

 

7.Raised Crosswalks

A raised crosswalk is a flat raised area covering the entire intersection with ramps on all approaches. The raised area is often constructed with bricks or other textured materials. The crosswalk is usually raised to the sidewalk level of slightly below the sidewalk level.

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Last Updated: August 3, 2009