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OCR for page 29
SECTION 4 Treatment Descriptions 4.1 Overview This section provides a summary of the findings reported in published literature on potential speed reduction treatments. Some of the reported treatments originate from applications for roadway segments; others are specific intersection applications. Once the intersection charac- teristics described previously in Section 3 have been assessed, the user can apply this informa- tion to help determine which treatment(s) may be appropriate at a specific location. This section contains an overview of each treatment, as well as more detailed descriptions, summaries of applicability and pertinent considerations such as maintenance, discussions of potential layouts and designs, and summaries of the documented effectiveness of each treatment in reducing speeds and improving safety. The treatments discussed are Dynamic warning signs, Transverse pavement markings, Transverse rumble strips, Longitudinal rumble strips, Wider longitudinal pavement markings, Roundabouts, Approach curvature, Splitter islands, Speed tables and plateaus, Reduced lane width, Visible shoulder treatments, and Roadside design features. In some cases, more than one treatment may be appropriate for a given intersection. To apply a treatment, users select a target speed and determine the location upstream of the intersection where sufficient distance is provided for drivers to react to potential con- flicts related to the intersection when traveling at the target speed. A transition area is needed upstream of this target speed location to allow drivers to decelerate from their segment speed. The transition length and target speed location help determine an appropriate treat- ment layout. The information provided in this section should be considered in tandem with appropriate local engineering practices and professional judgment related to the site-specific situation. 29