Pilot Testing of SHRP 2 Reliability Data and Analytical Products: Washington (2014) / Chapter Skim
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62 CHAPTER 6 Pilot Testing and Analysis on SHRP 2 L07 Product 6.1 Tool Introduction and Interface The objective of SHRP 2 L07 is to evaluate the cost-effectiveness of geometric design treatments in reducing nonrecurrent congestion. The L07 products help estimate traffic operational effectiveness and measure economic benefits of various design treatments.
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63 o Emergency pull-off (rural area) o Extra high median barrier (eliminate rubbernecking)
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64 Figure 6.3. Warning dialog for the OS X 10.6.8 operating system.
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65 Figure 6.6 for freeways. Figure 6.5.
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66 the incident duration reaches T The default values of T can be found in Figure 6.8.
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67 L07 team should help provide more details about how they get these values and the reasons for setting up such coefficients so that users can decide whether they need to update these factors regarding different roadway geometries, locations, weather characteristics, culture, and more. Figure 6.9.
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68 6.4 Performance Test Testing of L07 tool performance is conducted in three folds: (1) a comparison study is made with the DRIVE Net system to test the MOE sub-output, (2)
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69 (a) Output of DRIVE (b)
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70 Figure 6.12 shows the TTI curves calculated from single-loop data and the L07 tool. Three different hours (3:00 a.m., 8:00 a.m., and 5:00 p.m.)
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71 Figure 6.12. Comparison of outputs from single-loop detector data and L07 tool.
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72 6.4.3 Case Study To test the effectiveness of the L07 tool, the research team prefers finding a completed project with the same scope within Washington State. However, as the tool involves only 16 specific design treatments as mentioned in Section 6.1, an effective comparison requires a rigorous selection among previous construction projects.
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73 Existing southbound cable barrier was left in place to provide redundant protection. The project also widened the median shoulders to 10 feet, bringing them to current standards.
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74 hour demand slightly increased after the construction. Thus, the treatment did not result in a significant increase in traffic demand.
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75 Table 6.1. Incident Numbers for I-5 Mileposts 199–209 Before After Decrease Year 2006 2007 2008 Mean 2011 2012 Mean % Property damaged only 17 23 30 23.3 2 8 5 78.6 Minor injury 6 3 7 5.3 3 2 2.5 53.1 Fatality 1 1 2 1.3 0 0 0 100 Non-crash 575 625 627 609 136 130 133 78.2 Total 599 652 666 639 141 140 140.5 78.0 Summarizing Table 6.1, the conclusion can be drawn that the treatment had a significantly positive effect on reducing traffic incidents, especially severe incidents.
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76 Figure 6.16. L07 tool crash when crash reduction percentage is input at or near 100% (as in box for Minor Injury crashes at left)
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77 Figure 6.17. L07 tool output for benefit–cost analysis.
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78 6.5 Test Conclusions The research team believes that the L07 methodology on computing TTI curves should be further studied and compared. Neither the output comparison between L07 and DRIVE Net nor the software accuracy comparison between L07 before-treatment curve [see Figure 6.18 (b)
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