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Capacity Manual (HCM) being different from maximum throughput. The user should keep this in mind while using the tool. The standard capacity of 2,400 vphpl corresponding to a FFS of 70 mph was used for the I-5 facility. 6.4 Results of the I-5 Scenario Testing As with the C11 Reliability Tool, the L07 Analysis Tool was run with scenarios on both the I-5 facility in Orange County and the I-210 facility in the urbanized area of Los Angeles County. For the I-5 facility, several scenarios were tested: ⢠Baseline Calibration Test ⢠Initial Treatment Tests ⢠Incident Management (Custom Treatment Incidents) Test ⢠Operational Improvements (Custom Treatment Flow) Test ⢠Dynamic Ramp Metering (Custom Treatment Flow) Test ⢠High-Occupancy Vehicle + GP Widening (Custom Treatment Flow) Test The initial treatments tested were only those applicable for implementation in an urban freeway facility. Of the 19 available L07 tool treatment strategies, 14 treatment strategies were tested. Wildlife crash reduction, anti-icing systems, snow fence, blowing sand, and custom raw treatments were not tested, since they were considered inappropriate for the I-5 facility. The reliability results of the 6.5-mile I-5 facility segment are shown in Figure 6.11. The L07 Analysis Toolâs TTI estimates did not match the baseline conditions measured in PeMS as well as the results produced by the C11 tool. This may be due in part to the differences in capacity used. The C11 tool estimated reliability based on a capacity of 2,100 passenger cars per hour per lane (pcphpl) while the L07 tool estimated reliability based on a capacity of 2,400 vphpl. Therefore, the L07 tool-adjusted capacity is even higher. This results in a baseline condition that is not as well-calibrated. 113
Figure 6.11. Mean TTI results for I-5 baseline condition. Initial Treatment Tests The team evaluated the applicability of the L07 analytic toolâs 19 available treatments to the I-5 facility. Four treatments (i.e., wildlife crash reduction, anti-icing systems, snow fence, and blowing sand) were deemed to be inapplicable to Southern California conditions. Additionally, Customer Raw Treatment was not tested, as it was not applicable to the project scenarios tested in the I-5 CSMP (Caltrans 2012). The study team performed initial runs on each of the remaining 14 treatments utilizing the toolâs default input values. (Two additional custom treatments also were run.) Figure 6.12 provides a summary of the results of these runs. 114
Figure 6.12. Summary TTI results of initial treatment tests for I-5. Figure 6.13 summarizes the present value of reliability benefits for 12 default design treatments tested for the I-5 facility. The largest reliability benefits are due to control turnarounds, moveable cable barriers, emergency crossovers, emergency access, and drivable shoulders. The L07 tool includes default costs for each of these design treatments. As shown in Figure 6.14, these costs result in unreasonably high benefit-cost ratios, with many in the 100s. The lowest benefit-cost ratio is for an alternating shoulder with a benefit-cost ratio of 8.7. These high ratios are due to low default costs in the tool relative to right-of-way costs in Southern California and the currently high unreliability along the facility. 115
Figure 6.13. Present value of reliability benefits for L07 default design treatments on I-5. Figure 6.14. Benefit-cost ratios for L07 default design treatments on I-5 using model costs. Incident Management Test As with the C11 tool, the team used the L07 tool to test the effects of a reduction in incident duration that had been tested earlier in the I-5 CSMP (Caltrans 2012). This test assumes that enhanced incident management will reduce the average duration of a severe incident from 45 minutes to 30 minutes. As seen in Figure 6.15, the L07 tool provides a Custom Treatment Incidents module that allows for the input of average incident durations. Given that the CSMP scenario was intended to apply to severe collisions, the team applied the incident duration reduction to Major Injury & Fatal crashes only. A run was performed with average durations of 45 minutes for those types of crashes, and another run with durations of 30 minutes for the same types of crashes. 116
Figure 6.15. Custom treatment incidents inputs for I-5 incident management test. As seen in Figure 6.16, the L07 tool estimates that enhanced incident management results in improved reliability. When compared with the earlier results from the C11 tool (see Figure 5.12), the L07 tool appears to be less sensitive to incident reduction times than the C11 tool. As seen in Figure 6.17, the percent reduction in TTI was greatest during peak periods. 117
Figure 6.16. Mean TTIs on I-5 for incident management test. Figure 6.17. Comparison of mean TTI and percent reduction on I-5 for incident management test. Capacity Adjustment Tests The team also utilized the L07 toolâs Custom Treatment Flow module to test several additional scenarios identified in the I-5 CSMP. Figure 6.18 shows the capacity adjustments for the high- occupancy vehicle plus GP widening projects. 118
Figure 6.18. Custom treatment flow inputs for I-5 capacity adjustment tests. 119
