Communicating Changes in Horizontal Alignment (2006) / Chapter Skim
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Pages 19-22
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From page 19... ...
• An advisory speed plaque (W13-1) may be used to indicate the speed for the change in horizontal alignment.
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From page 20... ...
The participants in the practitioner focus groups identified the need for better guidance on when to use supplemental TCDs at horizontal curves. The practitioner survey revealed a wide variation in the use of chevrons: from using them on all curves when an advisory speed plaque is used to only using them when there is a 6° or greater degree of curvature.
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From page 21... ...
• Ninety-five percent of the respondents to the driver survey said arrows and chevrons helped them to successfully negotiate horizontal curves. • The driver survey respondents identified visibility and unexpected events as factors that cause them problems and where additional guidance would be beneficial.
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From page 22... ...
An engineering study shall be documented. It is argued here that the definition is too general for the purposes of placing TCDs on horizontal curves; it is thus recommended that a more explicit list of factors to be considered be included in the definition.
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