Synthesis of Safety for Traffic Operations - Transports Canada

More documents

Recommendations

Info

Synthesis of Safety for Traffic Operations March 2003 CHAPTER 3: INTERSECTION CONTROL Signalization Agent (1988) Agent (1988) in a comprehensive study of 65 rural, high-speed intersections in Kentucky, examined the effects of intersection control on crashes. The sites were selected to provide a variety of traffic volumes, roadway geometrics, and traffic control. The 65 locations were comprised of 47 signalized sites, 15 minor street stop-controlled sites, and 3 all-direction stop-controlled intersections. Sixteen of the 18 unsignalized locations were supplemented with intersection control beacons. Other forms of traffic control at the study sites varied from site-to-site, ex., advance warning, signal phasing, stop lines, transverse rumble strips, etc. Using a cross-sectional analysis of the study sites, Agent reported the crash rates shown in Table 3.1. The number of intersections exceeds 65, because some of the sites had changes in intersection control during the study period. TABLE 3.1: Crash Rates at Rural High-Speed Intersections in Kentucky Control Type No. of Sites Crashes Crash rate (per MV) CMF* Stop Sign 27 338 1.1 --- Stop + Beacon 37 541 1.2 1.09 Traffic Signal 46 1290 1.2 1.09 * - Assuming a stop sign as the base condition. Using a naïve before-after study of crash frequency, Agent also examined the effects of changing intersection control on safety (Table 3.2). TABLE 3.2: The Effect of Signalization of Crashes in Kentucky Intersection Control Crash rate No. Sites Before After Before After CMF Stop sign Stop+Beacon 11 1.1 1.0 0.91 Stop sign Traffic Signal 16 1.3 1.8 1.38 Stop+Beacon Traffic Signal 20 1.4 1.1 0.79 Finally, Agent provides information on the severity of crashes at all locations, as shown in Table 3.3. Page 15
Intersection Control TABLE 3.3: Crash Severity for Kentucky Intersections Crash Severity Proportion of Crashes (%) Stop Sign Stop + Beacon Signal State wide Fatal 1.5 2.6 0.9 0.2 Injury 37.2 39.6 34.1 23.6 PDO 61.3 57.8 65.0 76.2 It is difficult to extract any meaningful conclusions from this research. The results of the cross-sectional analysis and the before-after study provide conflicting evidence – in the cross-sectional study adding a beacon to an unsignalized location should produce an increase in crashes; in the before-after study there is a decrease. Furthermore, replacing a stop+beacon with a signal exhibits no change in crash rate in the cross-sectional study, but a fairly substantial decrease in crash rate in the before-after study. Lalani (1991) The City of San Buenaventura, California as part of a Comprehensive Safety Program undertook signalization of several intersections as a safety improvement (Lalani, 1991). Sites were selected because they had three or more crashes in a one-year period, the high crash locations. The results from a naïve before-after analysis using crash frequency from four of the signal installations are shown in Table 3.4. The before and after periods were one year. TABLE 3.4: Safety Impacts of Signalization in San Buenaventura, California Location Crashes Before After CMF A 5 2 0.40 B 8 1 0.13 C 17 0 0.00 D 4 3 0.75 Totals 34 6 0.18 Lalani does not account for exposure in the safety analysis but reports that traffic volumes in the city increase at an average rate of 6% per annum. Poch and Mannering (1996) In an attempt to determine the interactions between intersection approach characteristics and crash occurrence, Poch and Mannering (1996) developed crash prediction models for 63 intersections in Bellevue, Washington. The intersections were located in urban Page 16
Page 1 and 2: Transport Canada Transports Canada
Page 4: Synthesis Of Safety For Traffic Ope
Page 8 and 9: DISCLAIMER The material presented h
Page 10 and 11: EXECUTIVE SUMMARY Traffic operation
Page 12 and 13: Synthesis of Safety for Traffic Ope
Page 16 and 17: TABLE OF CONTENTS DISCLAIMER REJET
Page 20 and 21: LIST OF TABLES TABLE 3.1: Crash Rat
Page 24: Chapter 1: Chapter 1: Introductio I
Page 27 and 28: Introduction Before proceeding, a f
Page 29 and 30: Introduction Literature regarding t
Page 31 and 32: Introduction The current science of
Page 33 and 34: Introduction adequate size control
Page 35 and 36: Introduction In concluding this sec
Page 42: Chapter 3: Chapter 3: Intersectio I
Page 47 and 48: Intersection Control TABLE 3.5: CMF
Page 49 and 50: Intersection Control Vancouver Regi
Page 51 and 52: Intersection Control V m = the sum
Page 53 and 54: Intersection Control where: X1 = 0
Page 55 and 56: Intersection Control Region of Durh
Page 57 and 58: Intersection Control TABLE 3.17: CM
Page 59 and 60: Intersection Control The predictor
Page 63 and 64: Intersection Control program includ
Page 65 and 66: Intersection Control TABLE 3.26: Me
Page 67 and 68: Intersection Control TABLE 3.29: St
Page 69 and 70: Intersection Control TABLE 3.32: Ni
Page 73 and 74: Intersection Control It is noted th
Page 75 and 76: Intersection Control Sayed et al (1
Page 77 and 78: Intersection Control Signal Clearan
Page 79 and 80: Intersection Control The CMFs are 0
Page 81 and 82: Intersection Control also examined
Page 83 and 84: Intersection Control Shebeeb (1995)
Page 85 and 86: Intersection Control approaches at
Page 89 and 90: Intersection Control TABLE 3.56: Sa
Page 94 and 95:
Synthesis of Safety for Traffic Ope
Page 96 and 97:
Page 98 and 99:
Page 100 and 101:
Page 102:
Chapter 5: Chapter 5: Pavement Pave
Page 105 and 106:
Pavement Markings The study methodo
Page 107 and 108:
Pavement Markings Hall (1987) Hall
Page 109 and 110:
Pavement Markings TABLE 5.8: Safety
Page 111 and 112:
Pavement Markings THIS PAGE IS INTE
Page 114 and 115:
Page 116 and 117:
Page 118 and 119:
Page 120 and 121:
Page 122 and 123:
Page 124:
Chapter 7: Chapter 7: Bicycle Bicyc
Page 127 and 128:
Bicycle Safety TABLE 7.1: Safety Im
Page 130 and 131:
Page 132 and 133:
Page 134 and 135:
Page 136 and 137:
Page 138 and 139:
Page 140 and 141:
Page 142 and 143:
Page 144 and 145:
Page 146 and 147:
Page 148:
Chapter 9: Chapter 9: Turn Lanes Tu
Page 151 and 152:
Turn Lanes TABLE 9.2: Safety Impact
Page 153 and 154:
Turn Lanes Vogt determined that a l
Page 155 and 156:
Turn Lanes 1998 one of their high c
Page 157 and 158:
Turn Lanes Section TABLE 9.10: Safe
Page 159 and 160:
Turn Lanes A T = ADT 0.91 L 0.852 e
Page 161 and 162:
Turn Lanes CMF = 1 - 0.7 P lt/d 0.0
Page 163 and 164:
Turn Lanes occurred within 250 feet
Page 166 and 167:
Page 168 and 169:
TABLE 10.3: Speed Changes Resulting
Page 170 and 171:
Sites Where Applied 1 URBAN Island
Page 172 and 173:
Forbes and Gill (2000) undertook a
Page 174 and 175:
Ideally, three years of before and
Page 176 and 177:
Kermit and Hein (1962) looked into
Page 178 and 179:
The effects of the transverse pavem
Page 180:
Chapter 11: Chapter 11: Other Other
Page 183 and 184:
Other Safety Issues collisions per
Page 185 and 186:
Other Safety Issues THIS PAGE IS IN
Page 188 and 189:
Page 190 and 191:
Page 192 and 193:
Page 194 and 195:
Page 196 and 197:
Page 198 and 199:
Page 200 and 201:
Page 202 and 203:
Page 204 and 205:
Page 206 and 207:
Page 208 and 209:
Page 210 and 211:
Page 212 and 213:
Page 214 and 215:
Page 216 and 217:
Page 218 and 219:
Page 220:
References References
Page 223 and 224:
References Bloch SA (1998) “Compa
Page 225 and 226:
References Hamilton Associates (199
Page 227 and 228:
References Lee JT, Maleck TL, and T
Page 229 and 230:
References Polanis SF (1998) “Do
Page 231 and 232:
References Vancouver, City of (1999
Page 233 and 234:
References THIS PAGE IS INTENTIONAL
Page 236 and 237:
Page 238 and 239:
Page 240 and 241:
Page 242:
Appendix B: Critical R Appendix B:
Page 245 and 246:
Critical Reviews Worksheet for Eval
Page 247 and 248:
Critical Reviews 2. Are the expecte
Page 250 and 251:
Page 252 and 253:
Page 254 and 255:
Page 256 and 257:
Page 258:
Appendix D: Appendix D: How to Use
Page 261 and 262:
How to Use Safety Performance Funct
Page 263 and 264:
How to Use Safety Performance Funct
show all

Synthesis of Safety for Traffic Operations - Transports Canada

You also want an ePaper? Increase the reach of your titles

Delete template?

Save as template?