Technical Reports

Railroad Signal Color and Orientation: Effects of Color Blindness and Criteria for Color Vision Field Tests

  • 20
  • Mar
  • 2015
AUTHOR: Federal Railroad Administration
SUBJECT: Human Factors
KEYWORDS: Railroad Signals; Signal Color; Signal Orientation; Medical Standards for Color Vision for Locomotive Engineers and Conductors; Color Vision; Color Vision Field Tests; Pseeudoisochromatic Plate Tests; Human Error; Signal Detection Theory
ABSTRACT: This report concerns two issues: 1) whether color vision is necessary for locomotive crews who work on railroads where the signal system is either completely redundant with regard to signal color and signal orientation or the signal system only uses signal orientation; 2) what criteria should the railroad industry use for a valid, reliable, and fair field test of color vision. These two sets of issues are discussed together because they both relate to FRA’s Medical Standards Guidelines for locomotive engineers (49 CFR 240, Appendix F) and conductors (49 CFR 242, Appendix D) and to NTSB recommendations (NTSB 2013-18 and 2013-19) that FRA establish a field test for color vision for railroad employees who fail standard tests of color vision such as pseudoisochromatic plate tests. In the event that FRA considers reviewing its regulations regarding color vision, this information will be relevant and useful.
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