Consideration of Roadside Features in the Highway Safety Manual (2022) / Chapter Skim
Currently Skimming:
Pages 36-62
The Chapter Skim interface presents what we've algorithmically identified as the most significant single chunk of text within every page in the chapter.
Select key terms on the right to highlight them within pages of the chapter.
From page 36... ...
36 SPFEDGE DERIVATION Many model constructs were explored. This research considered speed as a major design constraint, however, it was revealed that speed does not present a clear trend toward predicting ROR crash frequency.
|
From page 37... ...
37 Models were developed by crash edge and are documented below. For some crashes, the edge could not be determined, however, it was important to maintain "unknown edge" crashes in the counts of total frequency.
|
From page 38... ...
38 • Consider only segments with four foot left shoulders: 25,414 segments. A summary of the filtered dataset is provided in Table 14.
|
From page 39... ...
39 Table 15. Correlation Matrix for Divided Highway ROR Events and Data Elements.
|
From page 40... ...
40 Table 16. Resulting Rural Divided Highway SPFEDGE Coefficients and Fit Statistics.
|
From page 41... ...
41 Table 17. Derivation of Rural Divided Highway SPFEDGE Coefficients.
|
From page 42... ...
42 Table 19. Correlation Matrix for Undivided Highway ROR Events and Data Elements.
|
From page 43... ...
43 Table 20. Resulting Rural Undivided Highway SPFEDGE Coefficients and Fit Statistics.
|
From page 44... ...
44 Table 21. Rural Undivided Highway SPFEDGE Coefficients.
|
From page 45... ...
45 Table 22. Descriptive Statistics of Filtered Multi-State Urban Divided Highway Dataset.
|
From page 46... ...
46 Table 24. Resulting Urban Divided Highway SPFEDGE Coefficients and Fit Statistics.
|
From page 47... ...
47 Table 25. Derivation of Urban Divided Highway SPFEDGE Coefficients.
|
From page 48... ...
48 Table 27. Correlation Matrix for Multi-State Urban Undivided Highway Dataset.
|
From page 49... ...
49 Table 28. Resulting Urban Undivided Highway SPFEDGE Coefficients and Fit Statistics.
|
From page 50... ...
50 Table 29. Derivation of Urban Undivided Highway SPFEDGE Coefficients.
|
From page 51... ...
51 Table 31. Undivided Highway SPFEDGE Coefficients.
|
From page 52... ...
52 Figure 11. Proportion of Urban Divided Highway Vehicle ROR Crashes by Edge and AADT.
|
From page 53... ...
53 Figure 13. Proportion of Urban Undivided Highway Vehicle ROR Crashes by Edge Mile and AADT.
|
From page 54... ...
54 Figure 15. Frequency of Urban Divided Highway ROR Crashes by Edge.
|
From page 55... ...
55 Figure 17. Frequency of Rural Undivided Highway ROR Crashes by Edge.
|
From page 56... ...
56 Figure 19. Comparison of Urban and Rural Undivided SPFEDGE.
|
From page 57... ...
57 Figure 20. Hutchinson and Kennedy Encroachment Frequency.
|
From page 58... ...
58 Figure 21. Cooper Base Encroachment Rate.[Cooper80]
|
From page 59... ...
59 Ray et al. reanalyzed the so-called Cooper data and documented the findings in the NCHRP 22-27 final report.
|
From page 60... ...
60 Figure 23. RSAPv3 Tabulated Encroachment Model.
|
From page 61... ...
61 Figure 24. Comparison of Divided Models for Encroachments and Crashes per Mile per Year.
|
From page 62... ...
62 Figure 25. Comparison of Undivided Models for Encroachments and Crashes per Mile per Year.
|
Key Terms
This material may be derived from roughly machine-read images, and so is provided only to facilitate research.
More
information on Chapter Skim is available.