Project No. NCHRP 13-02 GUIDELINES FOR THE SELECTION AND APPLICATION OF WARNING LIGHTS ON ROADWAY OPERATIONS EQUIPMENT APPENDICES Prepared for National Cooperative Highway Research Program Transportation Research Board National Research Council Ronald B. Gibbons, Suzanne E. Lee, Brian Williams Virginia Polytechnic and State University Blacksburg, VA 24061 and C. Cameron Miller National Institute For Standards and Technology Gaithersburg , MD 20899-8442 March 31, 2008 GUIDELINES FOR THE SELECTION AND APPLICATION OF WARNING LIGHTS ON ROADWAY OPERATIONS EQUIPMENT APPENDICES LIST OF FIGURES .......................................................................................................... 7 LIST OF TABLES .......................................................................................................... 11 APPENDIX A - LITERATURE REVIEW................................................................... 13 Driver Visual Perception........................................................................................... 13 Hazard Detection and Recognition ........................................................................... 15 Flashing Warning Lights........................................................................................... 18 Flash Frequency........................................................................................................ 21 Signal Size ................................................................................................................ 22 Hazard Analysis........................................................................................................ 26 Environment Complexity.......................................................................................... 27 State Practices for Roadway Warning Lights ........................................................... 29 Flashing Light Measurement Issues.......................................................................... 31 Retroreflective Tape.................................................................................................. 34 SAE Standards .......................................................................................................... 35 Survey of Current Equipment Available................................................................... 35 Literature Review Conclusions................................................................................. 40 APPENDIX B. IDENTIFICATION OF RELEVANT FACTORS ............................ 41 Knowledgeable Practitioner Survey.......................................................................... 44 Primary Factors......................................................................................................... 44 Secondary Factors..................................................................................................... 45 APPENDIX C. PHOTOMETRIC CHARACTERIZATION EXPERIMENT......... 55 Experimental Method................................................................................................. 55 Time-averaged chromaticity ..................................................................................... 55 Time-averaged luminous intensity............................................................................ 57 Waveform and Repetition rate.................................................................................. 61 Data Analysis............................................................................................................... 62 Results.......................................................................................................................... 62 APPENDIX C1 – TABLE OF LIGHTS AND LIGHT CHARACTERISTIC SUMMARIES 67 APPENDIX D. STATIC SCREENING EXPERIMENT ............................................ 73 Experimental Methods ............................................................................................... 73 Experimental Design................................................................................................. 73 Participants................................................................................................................ 88 Apparatus .................................................................................................................. 89 Methods..................................................................................................................... 96 Data Analysis............................................................................................................ 98 Results.......................................................................................................................... 98 Source, Intensity and Color Comparisons ................................................................ 98 Flash Characteristics ............................................................................................... 107 Strobe Lights........................................................................................................... 112 Rotating Beacons .................................................................................................... 116 3 Passive..................................................................................................................... 120 Beacon Position ...................................................................................................... 123 Vehicle Recognition Results................................................................................... 126 Photometric Comparison ........................................................................................ 130 Discussion .................................................................................................................. 137 Color ....................................................................................................................... 138 Effective Intensity................................................................................................... 138 Flash Pattern............................................................................................................ 138 Light Source Selection............................................................................................ 138 Retroreflective Tape................................................................................................ 138 Lamp Location........................................................................................................ 138 APPENDIX D1. SCREENING EXPERIMENT INFORMED CONSENT AND QUESTIONNAIRES .................................................................................................... 139 APPENDIX D2. PARTICIPANT CHARACTERISTICS AND QUESTIONNAIRE RESULTS ......................................................................................................................................... 145 Screening Experiment Participant Characteristics.................................................. 145 Driving Comfort in Various Weather Conditions (Screening Experiment) ........... 146 Opinions on Maintenance Vehicles and Lights (Screening Experiment)............... 146 Performance Experiment Participant Characteristics ............................................. 148 APPENDIX D3. ANOVA RESULTS FOR ALL COMPARISONS IN STATIC SCREENING EXPERIMENT ............................................................................................................. 151 Halogen Strobe Comparison.................................................................................... 151 Halogen LED Comparison....................................................................................... 154 Strobe LED Comparison.......................................................................................... 156 Flash Characteristics ................................................................................................ 158 Strobe Lights – Flash Pattern and Intensity .......................................................... 160 Strobe Lights – Color and Intensity........................................................................ 161 Rotating Beacons – Flash Pattern and Intensity.................................................... 162 Rotating Beacons – Color and Flash Pattern ......................................................... 164 Passive........................................................................................................................ 166 Beacons – Location and Lamp Type....................................................................... 167 APPENDIX E. PERFORMANCE EXPERIMENT................................................... 169 Experimental Methods ............................................................................................. 169 Experimental Design............................................................................................... 169 Participants.............................................................................................................. 176 Apparatus ................................................................................................................ 176 Methods................................................................................................................... 181 Data Analysis.......................................................................................................... 187 Results........................................................................................................................ 188 Lane-Change