Pilot Testing of SHRP 2 Reliability Data and Analytical Products: Southern California (2014)

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6.5 Results of the I-210 Scenario Testing To date, the team has tested various scenarios of the L07 tool utilizing the I-210 facility in an effort to better understand the tool’s behavior: • Split Segment Test (complete) • Initial Treatment Tests (complete) • Incident Duration Test (complete) • Peak Capacity Tests (in progress) Split Segment Test As with the C11 tool, the L07 tool was run initially using the full 16-mile urbanized segment of the I-210 facility. Then it was run separately for two smaller segments to determine whether the tool would produce more accurate results with smaller segments. The study team used the same method for testing the smaller segments as it had in the C11 tool testing. As shown in Figure 6.19, the facility was split into segments according to the number of lanes in one direction of travel. Figure 6.19. I-210 eastbound segmentation. The reliability results of the full 16-mile urbanized segment of I-210 are shown in Figure 6.20. Note that the TTI curves in this figure differ from those founding in Figure 6.10 (Baseline Condition Estimation) since the baseline condition estimation was ultimately performed for the four-lane segment rather than for the full 16-mile facility. 120

Figure 6.20. Mean TTI on the I-210 for full 16-mile segment. Unlike the C11 tool, the L07 tool produced TTI results closer to PeMS data for the full 16-mile segment (Figure 6.20) than for the five-lane segment (Figure 6.21). The team attributed this in part to the five-lane segment being a short (5.3-mile) segment with non-standard traffic patterns due to the proximity of the I-210/SR-134 interchange as well as high demand both entering and exiting the freeway through the heart of the City of Pasadena. Figure 6.21. Mean TTI on the I-210 for 5.3-mile five-lane segment. Results for the four-lane segment (Figure 6.22) were much closer to PeMS than either the original 16-mile or the five-lane segment (Figures 6.20 and 6.21). Given the relative quality of 121

the four-lane segment’s results, the team decided to perform all future tests using only the four- lane segment. Figure 6.22. Mean TTI on the I-210 for 10.2-mile four-lane segment. Initial Treatment Tests The study team evaluated the applicability of the L07 tool’s 19 available treatments for the I-210 facility. Four treatments (i.e., wildlife crash reduction, anti-icing systems, snow fence, and blowing sand) were deemed inapplicable. Initial runs were performed on each of the remaining 15 treatments using the tool’s default input values. Figure 6.23 provides a summary of the results of these runs. 122

Figure 6.23. Summary TTI results of initial treatment tests on the I-210. The tool appeared to provide little reliability benefit for most treatments, with the only real exception being Custom Raw Treatment. Given that these initial runs used the tool’s default input values, these results are intended merely to serve as a reference for future tests performed using any of these treatments. However, the relatively small impacts of these strategies on reliability suggest that the strategies or the inclusion of reliability benefits would not be very compelling to stakeholders. Figure 6.24 summarizes the present value of reliability benefits on the I-210 facility of 12 default design treatments. The largest reliability benefits are due to accessible shoulders, alternating shoulders, crash investigation sites, and emergency pullovers. Using the default costs in the L07 tool for these design treatments results in the benefit-cost ratios shown in Figure 6.25. As with the I-5 facility, the tool generates unreasonably high benefit-cost ratios, with many above 50. The lowest benefit-cost ratio is for a drivable shoulder with a benefit-cost ratio of 3.0. 123

Figure 6.24. Present value of reliability benefits for L07 default design treatments on the I- 210. Figure 6.25. Benefit-cost ratios for L07 default design treatments on the I-210 using model costs. Incident Duration Test The study team also used the L07 tool to test the effects of using enhanced incident management to reduce the average duration of a severe incident from 50 minutes to 38 minutes (using the same assumptions as in I-210 CSMP). Since the CSMP scenario applied only to serious collisions, the team applied reductions to Minor Injuries and Major Injury & Fatal crashes (see Figure 6.26). Runs were performed with average durations of 50 minutes and 38 minutes for those types of crashes (SCAG and Caltrans 2010). 124

Figure 6.26. Custom treatment incidents inputs for I-210 incident duration test. As seen in Figure 6.27, reducing incident durations results in a similarly shaped TTI curve with slightly lower TTI during the p.m. peak. Based on these results, the L07 tool appears to be less sensitive to incident reduction times than the C11 tool (see Figure 5.29). 125

Figure 6.27. Mean TTIs on the I-210 for incident duration test. As seen in Figure 6.28, the greatest percent reductions occurred when the initial TTIs were high. Figure 6.28. Comparison of mean TTI and percent reduction on the I-210 for incident duration test. 126

Capacity Adjustment Tests As with the C11 tool, the study team also tested additional scenarios identified in the I-210 CSMP (SCAG and Caltrans 2010) by using the L07 tool’s Custom Treatment Flow module (Figure 6.29). The results of these tests are shown in Figures 6.30 to 6.34. These tests show much smaller improvements than the comparable ones conducted using the C11 tool (see Figures 5.32 to 5.36). As a result of this analysis, the study team decided to use the C11 tool for the benefit- cost analysis shown in Chapter 9. 127

Figure 6.29. Custom treatment flow inputs for I-210 capacity adjustment tests. 128

Figure 6.30. Mean TTI on the I-210 for ramp metering test (scenarios 1 and 2). Figure 6.31. Mean TTI on the I-210 for advanced ramp metering test (Scenarios 3 and 4). 129

Figure 6.32. Mean TTI on the I-210 for auxiliary lane test (Scenarios 5 and 6). Figure 6.33. Mean TTI on the I-210 for ramp closure test (Scenarios 7 and 8). 130

Figure 6.34. Mean TTI on the I-210 for on-ramp and auxiliary lane test (Scenarios 9 and 10). 131