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From page 177... ... 177 A p p e n d i x B effect of Ramp Metering on Reliability on i-285 in Atlanta, Georgia Background The Georgia Department of Transportation (GDOT) has aggressively pursued ramp metering as a control strategy on Atlanta area freeways. Read the entire page →
From page 178... ... 178 Phase 2 report, a period of 75 days of data is insufficient to establish reliability, but is more than adequate to estimate average congestion, as measured by the Travel Time Index (TTI) here. Read the entire page →
From page 179... ... 179 July 16 period. Note that Section 5 had a data outage after October 15, which means that any results will be inconclusive for this section (although they have been reported) Read the entire page →
From page 180... ... 180 Table B.1. Section 5: I-285 Eastbound from I-75 to GA 400 (Peak Period, 7:15 to 8:45 a.m.; Section Length, 6.860 mi) Read the entire page →
From page 181... ... 181 Table B.3. Section 7: I-285 Eastbound from GA 400 to I-85 (Peak Period, 4:00 to 6:30 p.m.; Section Length, 5.861 mi) Read the entire page →
From page 182... ... 182 • As demonstrated in Chapter 4, the Buffer Index and the skew statistic generally increased as TTI dropped; the Buffer Index increased approximately 10%, and the skew statistic increased on three of the sections as TTI dropped. Section 5 showed a 3.6% decrease in the Buffer Index, but this section also showed the lowest drop in TTI (7.5%) Read the entire page →
From page 183... ... 183 Table B.8. Performance Measure Comparisons for I-210 Westbound in Los Angeles Time Period Average Travel Time Buffer Index Failure Rate Planning Time Index Skew Statistic Misery Index Before After Before After Before After Before After Before After Before After Peak hour 25.7 0.1 26.5 0.1 0.246 0.006 0.245 0.004 0.051 0.004 0.046 0.003 2.358 0.016 2.410 0.010 1.062 0.048 0.932 0.038 0.391 0.009 0.389 0.010 Peak period 23.9 0.1 25.0 0.1 0.312 0.005 0.303 0.003 0.098 0.003 0.095 0.003 2.327 0.009 2.391 0.010 1.151 0.030 1.050 0.028 0.491 0.007 0.499 0.009 Counterpeak 15.9 0.0 16.8 0.0 0.152 0.003 0.210 0.004 0.039 0.002 0.052 0.002 1.399 0.013 1.530 0.009 4.374 0.223 2.895 0.099 0.466 0.014 0.491 0.015 Midday 14.8 0.0 15.1 0.0 0.040 0.001 0.064 0.002 0.002 0.000 0.016 0.001 1.114 0.003 1.186 0.004 2.989 0.084 4.350 0.121 0.147 0.005 0.286 0.011 Weekday 16.8 0.0 17.2 0.0 0.398 0.004 0.423 0.003 0.148 0.001 0.154 0.001 1.928 0.005 2.024 0.005 24.515 0.280 16.458 0.201 0.850 0.003 0.884 0.003 All year 16.1 0.0 16.5 0.0 0.294 0.004 0.331 0.004 0.124 0.001 0.130 0.001 1.810 0.006 1.899 0.007 34.160 0.442 19.620 0.216 0.844 0.004 0.886 0.004 Note: Standard errors are shown in boldface. Read the entire page →
From page 184... ... 184 Figure B.6. Travel time density on I-210 westbound in Los Angeles, peak period. Read the entire page →
From page 185... ... 185 Table B.10. Performance Measure Comparisons for I-710 Northbound in Los Angeles Average Travel Time Buffer Index Failure Rate Planning Time Index Skew Statistic Misery Index Time Period Before After Before After Before After Before After Before After Before After Peak hour 19.9 0.1 17.0 0.1 0.337 0.011 0.238 0.007 0.098 0.005 0.065 0.003 2.330 0.040 1.874 0.031 2.401 0.108 1.940 0.081 0.754 0.028 0.682 0.027 Peak period 18.7 0.1 16.1 0.0 0.347 0.009 0.247 0.007 0.109 0.003 0.075 0.002 2.259 0.026 1.784 0.017 1.890 0.055 2.277 0.078 0.803 0.017 0.714 0.020 Counterpeak 19.1 0.1 18.9 0.1 0.358 0.005 0.319 0.005 0.126 0.003 0.100 0.003 2.185 0.017 2.082 0.011 1.721 0.060 1.476 0.043 0.625 0.012 0.538 0.007 Midday 15.3 0.0 14.7 0.0 0.169 0.009 0.124 0.005 0.063 0.003 0.040 0.002 1.657 0.019 1.444 0.013 4.006 0.198 2.305 0.082 0.645 0.018 0.497 0.014 Weekday 16.3 0.0 15.4 0.0 0.343 0.003 0.282 0.002 0.129 0.001 0.100 0.001 1.955 0.006 1.745 0.005 4.278 0.043 4.194 0.039 0.784 0.005 0.673 0.004 All year 15.5 0.0 14.8 0.0 0.325 0.002 0.257 0.002 0.129 0.001 0.097 0.001 1.855 0.007 1.659 0.004 6.328 0.078 8.684 0.131 0.797 0.006 0.671 0.004 Note: Standard errors are shown in boldface. Read the entire page →
From page 186... ... 186 Figure B.7. Travel time density on I-710 northbound in Los Angeles, peak hour. Read the entire page →
From page 187... ... 187 Figure B.8. Travel time density on I-710 northbound in Los Angeles, peak period. Read the entire page →
From page 188... ... 188 Table B.13. Summary Demand, Weather, and Incident Characteristics for I-580 Eastbound in San Francisco Bay Area Before After Demand AADT 110 111 K-factor 5% 5% Weather (number Rain 16 18 of days) Read the entire page →
From page 189... ... 189 Table B.14. Performance Measure Comparisons for I-580 Eastbound in San Francisco Bay Area Average Travel Time Buffer Index Failure Rate Planning Time Index Skew Statistic Misery Index Time Period Before After Before After Before After Before After Before After Before After Peak hour 14.2 0.2 11.1 0.1 0.347 0.014 0.349 0.007 0.126 0.014 0.101 0.004 3.685 0.064 2.986 0.036 1.149 0.120 1.974 0.076 0.666 0.047 0.705 0.018 Peak period 13.1 0.1 10.2 0.0 0.426 0.010 0.337 0.005 0.166 0.005 0.101 0.002 3.738 0.063 2.800 0.016 1.273 0.068 1.621 0.038 0.822 0.024 0.738 0.010 Counterpeak 7.1 0.0 6.5 0.0 0.156 0.004 0.170 0.005 0.014 0.004 0.053 0.002 1.526 0.011 1.585 0.025 1.614 0.119 3.324 0.108 0.363 0.032 0.693 0.028 Midday 7.6 0.1 6.9 0.0 0.140 0.010 0.223 0.006 0.056 0.006 0.080 0.002 1.886 0.081 1.762 0.024 2.514 0.174 4.470 0.129 0.941 0.095 0.802 0.024 Weekday 8.6 0.0 7.5 0.0 0.686 0.008 0.461 0.003 0.207 0.003 0.178 0.001 3.050 0.027 2.263 0.007 5.693 0.100 5.527 0.048 1.329 0.014 0.990 0.007 All year 7.8 0.0 7.1 0.0 0.612 0.012 0.446 0.002 0.174 0.002 0.171 0.001 2.833 0.019 2.136 0.006 7.041 0.132 8.676 0.073 1.412 0.014 0.997 0.005 Note: Standard errors are shown in boldface. Read the entire page →
From page 190... ... 190 Table B.15. Summary Demand, Weather, and Incident Characteristics for I-8 Westbound in San Diego Before After Demand AADT 49 46 K-factor 4% 5% Weather (number of days) Read the entire page →
From page 191... ... 191 Table B.16. Performance Measure Comparisons for I-8 Westbound in San Diego Time Period Average Travel Time Buffer Index Failure Rate Planning Time Index Skew Statistic Misery Index Before After Before After Before After Before After Before After Before After Peak hour 6.1 0.0 6.1 0.0 -0.001 0.000 0.002 0.002 0.000 0.000 0.004 0.001 1.000 0.000 1.015 0.001 NA NA NA NA 0.000 0.000 0.090 0.015 Peak period 6.1 0.0 6.1 0.0 -0.001 0.000 0.006 0.000 0.000 0.000 0.002 0.000 1.000 0.000 1.018 0.000 NA NA NA NA 0.000 0.000 0.055 0.005 Counterpeak 6.6 0.0 6.6 0.0 0.106 0.010 0.103 0.010 0.061 0.002 0.056 0.002 1.505 0.025 1.440 0.018 NA NA NA NA 0.892 0.034 0.811 0.029 Midday 6.1 0.0 6.1 0.0 -0.005 0.001 0.015 0.000 0.003 0.001 0.002 0.000 1.005 0.001 1.029 0.000 NA NA NA NA 0.081 0.010 0.058 0.005 Weekday 6.2 0.0 6.2 0.0 -0.013 0.000 0.003 0.000 0.021 0.001 0.018 0.001 1.034 0.001 1.037 0.001 NA NA NA NA 0.298 0.007 0.267 0.006 All year 6.2 0.0 6.2 0.0 -0.013 0.000 0.004 0.000 0.017 0.000 0.015 0.000 1.026 0.000 1.030 0.000 NA NA NA NA 0.254 0.005 0.228 0.005 Note: Standard errors are shown in boldface. Read the entire page →
From page 192... ... 192 Figure B.14. Travel time density on I-8 westbound in San Diego, peak period. Read the entire page →
From page 193... ... 193 Table B.18. Performance Measure Comparisons for I-8 Eastbound in San Diego Average Travel Time Buffer Index Failure Rate Planning Time Index Skew Statistic Misery Index Time Period Before After Before After Before After Before After Before After Before After Peak hour 7.3 0.0 7.1 0.0 0.283 0.008 0.266 0.007 0.085 0.004 0.077 0.004 1.737 0.016 1.647 0.017 3.136 0.233 7.800 0.901 0.575 0.022 0.604 0.023 Peak period 6.9 0.0 6.7 0.0 0.301 0.004 0.287 0.003 0.098 0.002 0.090 0.002 1.671 0.007 1.600 0.008 13.763 0.641 47.245 3.115 0.611 0.013 0.634 0.012 Counterpeak 6.0 0.0 6.0 0.0 -0.004 0.001 -0.006 0.001 0.007 0.001 0.033 0.002 1.018 0.001 1.035 0.005 NA NA NA NA 0.187 0.024 0.279 0.015 Midday 6.0 0.0 5.9 0.0 0.003 0.001 -0.001 0.001 0.010 0.001 0.009 0.001 1.034 0.002 1.022 0.001 NA NA NA NA 0.200 0.017 0.159 0.012 Weekday 6.3 0.0 6.2 0.0 0.169 0.005 0.120 0.006 0.091 0.001 0.080 0.001 1.462 0.004 1.405 0.003 NA NA NA NA 0.579 0.005 0.535 0.004 All year 6.2 0.0 6.1 0.0 0.050 0.003 0.014 0.001 0.071 0.001 0.065 0.001 1.371 0.005 1.336 0.003 NA NA NA NA 0.530 0.004 0.494 0.004 Note: Standard errors are shown in boldface. Read the entire page →
From page 194... ... 194 Table B.20. Performance Measure Comparisons for SR 52 Westbound in San Diego Average Travel Time Buffer Index Failure Rate Planning Time Index Skew Statistic Misery Index Time Period Before After Before After Before After Before After Before After Before After Peak hour 13.2 0.1 9.7 0.0 0.369 0.012 0.206 0.006 0.135 0.005 0.045 0.004 2.329 0.053 2.162 0.021 2.275 0.142 0.834 0.041 1.018 0.038 0.441 0.017 Peak period 13.0 0.1 9.3 0.0 0.427 0.008 0.257 0.004 0.163 0.003 0.068 0.003 2.414 0.037 2.177 0.013 7.613 0.711 0.662 0.017 1.223 0.033 0.524 0.014 Counterpeak 9.3 0.0 5.8 0.0 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 1.000 0.000 1.000 0.000 NA NA NA NA 0.000 0.000 0.000 0.000 Midday 9.3 0.0 5.8 0.0 -0.002 0.000 0.001 0.000 0.000 0.000 0.000 0.000 1.009 0.001 1.008 0.000 NA NA NA NA 0.045 0.009 0.042 0.006 Weekday 10.3 0.0 6.8 0.0 0.290 0.007 0.476 0.002 0.146 0.001 0.271 0.001 1.760 0.005 1.881 0.004 NA NA NA NA 1.111 0.010 0.805 0.006 All year 10.1 0.0 6.6 0.0 0.072 0.007 0.454 0.002 0.130 0.001 0.254 0.002 1.668 0.005 1.834 0.003 NA NA NA NA 1.042 0.009 0.813 0.004 Note: Standard errors are shown in boldface. Read the entire page →
From page 195... ... 195 Figure B.16. Travel time density on I-8 eastbound in San Diego, peak period. Read the entire page →
From page 196... ... 196 Figure B.18. Travel time density on SR 52 westbound in San Diego, peak period. Read the entire page →
From page 197... ... 197 Figure B.19. Peak hour travel time for Project B eastbound. Read the entire page →
From page 198... ... 198 Figure B.21. Peak hour travel time for Project C Read the entire page →
From page 199... ... 199 Figure B.23. Peak hour travel time for Project E2. Read the entire page →
From page 200... ... 200 Figure B.25. Peak hour travel time for Project H Read the entire page →
From page 201... ... 201 Figure B.27. Peak hour travel time frequency distribution for Project B westbound. Read the entire page →
From page 202... ... 202 Figure B.29. Peak hour travel time frequency distribution for Project E Read the entire page →
From page 203... ... 203 Figure B.31. Peak hour travel time frequency distribution for Project G Read the entire page →
From page 204... ... 204 Table B.23. Performance Measure Comparisons for Project B Eastbound Travel Time Index Buffer Index Planning Time Index Skew Statistic Misery Index On-Time at 45 mph (%) Read the entire page →
From page 205... ... 205 Table B.27. Performance Measure Comparisons for Project E2 TTI Buffer Index Planning Time Index Skew Statistic Misery Index On-Time at 45 mph (%) Read the entire page →
From page 206... ... 206 completion) Read the entire page →
From page 207... ... 207 NE 85th (traffic is moving from bottom to top in the diagrams) Read the entire page →
From page 208... ... 208 two GP lanes and one inside HOV lane in the segment of interest. This project added a third GP lane. Read the entire page →
From page 209... ... 209 on any given weekday dropped sharply, from 85% to 92% in previous years to 31% after construction. Figure B.36 illustrates that the improvement in the likelihood of having a heavily congested trip is significant throughout the a.m. Read the entire page →
From page 210... ... 210 to December 31, 2002) in an effort to minimize the effects of seasonal variation. Read the entire page →
From page 211... ... 211 with the previous year. The same increase was recorded for the median speed. Read the entire page →
From page 212... ... 212 were over 100% longer than free-flow speeds, but in 2003, they were only 60% longer. The grade separation ramp also significantly improved mainline throughput near the interchange. Read the entire page →
From page 213... ... 213 on the east side of the lake, as well as business development on the east side (e.g., Microsoft) Read the entire page →
From page 214... ... 214 significant throughout the a.m. peak period, and it demonstrates that ramp metering delayed the onset of congestion for the segment. Read the entire page →
From page 215... ... 215 Table B.39. SR 520 Eastbound Throughput at Montlake Boulevard (vehicles/hour) Read the entire page →
From page 216... ... 216 Figure B.43. Time–space speed contours in 2008 on SR 520 segment affected by ramp metering. Read the entire page →

From page 177...

... 177 A p p e n d i x B effect of Ramp Metering on Reliability on i-285 in Atlanta, Georgia Background The Georgia Department of Transportation (GDOT) has aggressively pursued ramp metering as a control strategy on Atlanta area freeways.