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Human Factors Guidelines for Road Systems - Collection C: Chapters 16, 17, 18, 19, 20, 22 (Tutorials 4, 5, 6), 23 (Updated), 24, 25, 26 (Updated) (2010) / Chapter Skim
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Conspicuity of Diamond Warning Signs under Nighttime Conditions
Pages 30-31

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
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From page 30...
... provides design considerations that specify that "devices should be designed so that features such as size, shape, color, composition, lighting or retroreflection, and contrast are combined to draw attention to the devices." As discussed in more detail below, a critical factor in facilitating the driver's ability to find and comprehend warning signs at night is to maximize the sign's visual conspicuity relative to surrounding background elements. The figure below illustrates the relationship between sign recognition by drivers, sign brightness, and the complexity of the sign's immediate environment.
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From page 31...
... Although sign conspicuity is clearly important, compliance with the specifications set by the MUTCD for sign shape and other characteristics is essential. Design Issues A key factor to consider in improving the conspicuity and visibility of highway signs is the importance of individual differences across the driver population.
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Key Terms

  • visual field
  • noise items
  • warning signs
  • sign brightness
  • brightness contrast

  • field decreases
  • diamond warning
  • luminance requirements
  • target increases
  • sign luminance

  • empirical data
  • expert judgment
  • traffic sign
  • sign information
  • driver population

  • irrelevant classes
  • overall density
  • study conducted
  • design issues
  • critical factor

  • surrounding background
  • research board
  • hue contrasts
  • determining nighttime
  • visual demands

  • traffic control
  • luminance levels
  • sign recognition
  • driver factors
  • immediate environment


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