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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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Chapter 24 - Glossary
Pages 88-93

The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.


From page 88...
... -- Equipment for use at signalized intersections that com municates pedestrian signal timing information in non-visual formats. Features include push button locator tone, tactile arrow, pushbutton information message, automatic volume adjustment, alert tone, actuation indicator, tactile map, Braille and raised print information, extended button press, passive pedestrian detection, and clearance interval tones.
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From page 89...
... Drop-off -- Deterioration of roadways caused when the edges of the pavement become destabi lized and eroded, resulting in a difference in height between the pavement surface and the roadside surface. Dynamic Characteristics -- Message properties that specify character movement such as time to display each message phase, to display blanking between phases of a multiphase message, and to flash one or more lines of a message.
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From page 90...
... Looming -- One of several dynamic characteristics of message signs, this term refers to increas ing the size of text or symbols over time in a message display. Luminous Intensity -- A measure of the perceived power emitted by a light source in a particu lar direction per unit solid angle.
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From page 91...
... Open-Loop Anticipatory Control Process -- Part of the steering control process in which drivers predict road curvature and required steering angle based on far-field visual cues. Optic Flow -- The visual pattern caused by moving forward, in which points close to the point of expansion move outward slower than points more peripheral to it.
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From page 92...
... To deter mine letter height divide the viewer reaction distance by the appropriate legibility index value (which varies depending on illumination, font style and case, as well as font color contrast to background)
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From page 93...
... Variable Message Sign (VMS) -- VMSs are electronic, reconfigurable signs placed above or near the roadway and used to inform motorists of specific conditions or situations.
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Key Terms

  • message signs
  • signal changes
  • message sign
  • changeable message
  • vehicle travels

  • dynamic message
  • variable message
  • specific conditions
  • pavement surface
  • signs placed

  • inform motorists
  • minor road
  • pavement markers
  • reconfigurable signs
  • letter height

  • clearance interval
  • font style
  • light source
  • raised pavement
  • distance traveled

  • roadway sign
  • passing lane
  • engineering handbook
  • viewer reaction
  • control process

  • available sight
  • traffic engineering
  • vehicle crossing
  • vehicle actually
  • stopping sight


    • This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
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