Pedestrian Signal Safety - AAA Foundation for Traffic Safety

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38 where: LPI = seconds between the onset of the WALK signal for pedestrians and the green indicator for vehicles, minimum 3-sec. duration ML = width of moving lane, in ft. PL = width of parking lane (if any), in ft. (Staplin et al. 2001) Empirical evidence suggests that LPIs increase pedestrian safety. Van Houten, Retting, Farmer, and Van Houten evaluated the effect of a 3-sec. LPI on pedestrian safety at three urban intersections in St. Petersburg, Florida. Pedestrian behavior and conflicts were the measures of effectiveness. For both left-turning and right-turning vehicles, there were fewer conflicts during the LPI condition than during the baseline period. Van Houten, Retting, Farmer, and Van Houten concluded that the use of the LPI made it somewhat easier for pedestrians to cross the street by allowing them to occupy the crosswalk before turning vehicles were permitted to enter the intersection (Van Houten et al. 2000). INTERSECTION OPERATIONS At signalized intersections, various traffic movements compete for time within the cycle length provided. Pedestrian crossings at intersections represent one such traffic movement and are served by a pedestrian phase. The 2003 edition of MUTCD states: Except as noted in the Option, the walk interval should be at least 7 seconds in length so that pedestrians will have adequate opportunity to leave the curb or shoulder before the pedestrian clearance time begins. The 2003 edition of MUTCD also states that the PCI should be sufficient to allow a pedestrian crossing in the crosswalk who left the curb or shoulder during the WALK interval to travel at a walking speed of 4.00 ft./sec. to at least the far side of the traveled way. Lowering the walking speed will result in a longer PCI and will potentially reduce the time available for other movements at a signalized intersection. A recent study, “The Continuing Evolution of Pedestrian Walking Speed Assumptions,” showed how varying the walking speed on an individual approach to an intersection affected the available intersection green time (LaPlante and Kaeser 2004). The effects were demonstrated using cycle lengths ranging from 60 sec. to 120 sec. and street widths ranging from 40 ft. to 120 ft. The relationship between these variables was expressed by the remaining signal green time to cycle length ratio (G/C) available for all traffic movements after the pedestrian phase for a single crossing had been determined based on a given walking speed, cycle length, and crossing distance. The G/C ratio is the proportion of green time available for other non-concurrent movements. Higher G/C ratios permit higher vehicle throughput and, many times, less time for pedestrians to cross a street. Conversely, lower G/C ratios permit lower vehicle throughput and, potentially, more pedestrian crossing time—often with tradeoffs in vehicular intersection efficiency. Intersections with short cycle lengths (60 sec.) and wide street widths (120 ft.) resulted in low G/C ratios, from 0.20 to 0.37 for the different walking speeds examined. Conversely, intersections with long cycle lengths (120 sec.) and short crossing distances for pedestrians (40 ft.) resulted in higher G/C ratios, from 0.82 to 0.85. It was noted that most traffic engineering applications would involve G/C ratios between these ranges, where a balance must be struck between pedestrian phase needs and vehicle phase needs (LaPlante and Kaeser 2004).
Gates, Noyce, Bill, and Van Ee expanded the work of LaPlante and Kaeser and conducted studies that considered the impact of slower walking speeds on intersection efficiency. They concluded that: • For intersection approaches where vehicular demand governs the amount of green time for through movements, a decrease in walking speeds is not likely to affect the amount of green time necessary to provide pedestrian clearance. • Narrow intersections are less affected by walking speeds or cycle length. • Longer cycle lengths do a better job of “absorbing” the impact of slower walking speeds on intersection efficiency. • The use of slower walking speeds for timing PCIs should not have an overly negative impact on signalized intersection efficiency, as long as the cycle length is greater than or equal to 90 sec., the crossing distance is not excessively wide, and the intersection is not at capacity. • Slower walking speeds may have a negative effect on vehicular traffic flows under the following conditions: SUMMARY o At intersection approaches where vehicular demand is low and pedestrian demand is high, a longer pedestrian clearance time likely will increase the green interval and the overall phase time for that approach. The longer phase will require either a reduction in other phase times, resulting in longer delays, or an increase in the cycle length, having potentially negative impacts on corridor progression. o Shorter cycle lengths o Wider crossings (Bowman and Vecellio 1994) The literature review provided information on published studies on PCD signals, pedestrian walking characteristics, and pedestrian signal operation. Several studies have been conducted on PCD signals (Mahach et al. 2002; Allsbrook 1999; Chester and Hammond 1998; Eccles, Tao, and Mangum 2004; and Singer and Lerner 2005). Overall, pedestrians appeared to understand and prefer PCD signals to TPS. Studies of the effect of PCD signals on pedestrian behavior were inconclusive (Eccles, Tao, and Mangum 2004; Singer and Lerner 2005; Farraher 1999; and Leonard and Juckes 1999). Leonard and Juckes and MnDOT found a generally positive effect on pedestrian behavior (Farraher 1999; and Leonard and Juckes 1999). Singer and Lerner and Huang and Zegeer found some negative effect on pedestrian behavior (Singer and Lerner 2005; and Huang and Zegeer 2000). Eccles, Tao, and Mangum concluded that the countdown did not negatively affect overall pedestrian crossing behavior (Eccles, Tao, and Mangum 2004). Walking speed is important for calculating pedestrian intervals at intersections. The reviewed studies 39
Page 1: Pedestrian Signal Safety for Older
Page 5 and 6: LIST OF TABLES Table/Page ES-1/19.
Page 7: LIST OF FIGURES Figure/Page 1/22. E
Page 11 and 12: LIST OF DEFINITIONS Access Board Th
Page 13: FOREWORD ABOUT THE SPONSOR This stu
Page 16 and 17: 16 Mark J. Kulewicz Director-Traffi
Page 18 and 19: 18 LITERATURE REVIEW FINDINGS • O
Page 20 and 21: 20 1. Based on the results observed
Page 22 and 23: 22 Figure 1. Example of a pedestria
Page 25 and 26: METHODS The project objectives were
Page 27 and 28: and 3.40 ft./sec. for pedestrians o
Page 29 and 30: the potential impact of various wal
Page 31 and 32: Pedestrian Start-Up Time Pedestrian
Page 33 and 34: • a PCD signal with both the coun
Page 35 and 36: six crosswalks experienced a signif
Page 37: where: W = duration of WALK indicat
Page 41 and 42: Table 3. Summary of empirical data
Page 43 and 44: Table 4. Summary of researcher reco
Page 45 and 46: SITE SELECTION/EFFECT OF DIFFERENT
Page 47 and 48: Walking Speeds The project team mea
Page 49 and 50: RESULTS AGENCY SURVEY FINDINGS Deta
Page 51 and 52: 5 0 . 0 % 4 5 . 0 % 4 0 . 0 % 3 5 .
Page 53 and 54: POSITIVE IMPACTS OF PEDESTRIAN COUN
Page 55 and 56: • Give third priority to signaliz
Page 57 and 58: 15th-Percentile Walking Speed The 1
Page 59 and 60: Table 10: Pedestrian signal complia
Page 61 and 62: Table 12. Older pedestrians remaini
Page 63 and 64: The case study intersections in Sal
Page 65 and 66: Five different traffic volume condi
Page 67 and 68: Minneapolis/St.Paul, Minnesota Figu
Page 69 and 70: Figure 10. Delay vs. volumes at Mon
Page 71 and 72: There was no change in overall LOS
Page 73 and 74: Figure 13. Delay vs. volumes at Ora
Page 75 and 76: Pedestrian Understanding and Prefer
Page 77 and 78: the countdown at the end of the FDW
Page 79 and 80: lengths are preferred for pedestria
Page 81 and 82: Table 23. Comparison of the literat
Page 83 and 84: observer was assigned to each inter
Page 85 and 86: APPENDIX A WEB-PEDESTRIAN COUNTDOWN
Page 87 and 88: PURPOSE OF SURVEY The purpose of th
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d) Plan to use during the next one
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Question 22 If you answered “yes
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Table A-1. Distribution of responde
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Table A-2. Respondent organizations
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Figure A-2 shows the distribution o
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6 0 .0 % 5 5 .0 % 5 0 .0 % 4 5 .0 %
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Figure A-7. Roadway characteristics
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PEDESTRIAN COUNTDOWN SIGNAL START/E
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PCD Signal Start/End Times Start of
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3. Seniors and other adults showed
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• No. Countdown timers encourage
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the crossing time remaining? Yes 20
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• None (n = 32) • Motorists spe
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PEDESTRIAN SAFETY FOR OLDER PEDESTR
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APPENDIX C: BROWARD COUNTY, FLORIDA
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BACKGROUND Broward County is locate
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DATA COLLECTION METHODOLOGY Pedestr
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For younger pedestrians, the mean w
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Pedestrians Under 65 Table C-6 show
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Pedestrians Left in Intersection At
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Table C-11. Pedestrian WALK and cle
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Figure C-2. Delay vs. volumes at ca
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Table C-13. Broward County, Florida
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APPENDIX D: MINNEAPOLIS/ST. PAUL, M
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BACKGROUND Minneapolis, in southeas
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• Lyndale Avenue and Franklin Ave
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Table D-2. Walking speeds for pedes
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Table D-4. Significance testing of
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Table D-7. Frequency and percentage
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SURVEY RESULTS A total of 150 pedes
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For the major street approaches, LO
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3.50 ft./sec. Figure D-6. Intersect
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SUMMARY In summary, the key results
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LIST OF TABLES Table/Page E-1/156.
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SITE SELECTION Engineering staff fr
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Twenty-two pedestrians with mobilit
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Older Pedestrians Table E-8 shows t
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EFFECT OF CHANGING WALKING SPEEDS O
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As shown in Table E-12, major stree
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3.50 ft./sec. Figure E-6. Intersect
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SUMMARY In summary, the key results
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LIST OF TABLES Table/Page F-1/176.
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SITE SELECTION The City of White Pl
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RESULTS Walking Speeds The walking
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cross. That is, at an intersection
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Table F-11. Pedestrian WALK and cle
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Table F-13. White Plains, New York:
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APPENDIX G: SALT LAKE CITY, UTAH CA
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BACKGROUND Salt Lake City is Utah
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Figure G-2 displays the type of ped
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Table G-2. Walking speeds for pedes
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Pedestrians with Impairments Pedest
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Older Pedestrians Table G-8 shows t
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EFFECT OF CHANGING WALKING SPEEDS O
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Figure G-3. Delay vs. volumes at ca
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Table G-13. Salt Lake City, Utah in
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APPENDIX H: ORANGE COUNTY, CALIFORN
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BACKGROUND Orange County, Californi
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Younger Pedestrians Table H-6 shows
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Figure H-2 shows the overall averag
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Figure H-2. Delay vs. volumes at ca
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Table H-13. Orange County, Californ
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APPENDIX I: MONROE COUNTY, NEW YORK
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COUNTY OF MONROE DEPARTMENT OF TRAN
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APPENDIX J: NATIONAL COMMITTEE ON U
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3. Add a new Guidance statement rec
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Guidance: Where the pedestrian clea
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Fugger, T.F., B.C. Randles, A.C. St
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Pedestrian Signal Safety - AAA Foundation for Traffic Safety

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