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From page 109... ... C-1 A P P E N D I X C Probability of Crash Severity (PSEVj) CONTENTS Chapter 1 Introduction Chapter 2 Method Chapter 3 Available Data Data from the Literature New Data Gathered Chapter 4 Estimate Unreported Crashes Chapter 5 Determine P(KA\|C) Read the entire page →
From page 110... ... C-2 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers CHAPTER 1 INTRODUCTION P(KA\|C) , the conditional probability of a severe or fatal (i.e., KA) Read the entire page →
From page 111... ... Probability of Crash Severity (PSEVj) C-3 CHAPTER 2 METHOD The process used with RSAPv3 to model crash severity includes the ability to account for unreported crashes and to scale crash severity by the posted speed limit (PSL) Read the entire page →
From page 112... ... C-4 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers KABCO + Unreported Crashes of all reported severities plus the estimated unreported crashes from EFCCR step 3 for all posted speed limits. In this extension of the procedure, rather than calculating an EFCCR (i.e., Step 4, above) Read the entire page →
From page 113... ... Probability of Crash Severity (PSEVj) C-5 CHAPTER 3 AVAILABLE DATA Data from the Literature NCHRP Project 22-12(03) Read the entire page →
From page 114... ... C-6 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Table C-2 Nebraska Crash Severity Distribution (after Ray 2021) PSL K A B C O 29" Vertical Wall 50 mph or less 0 0 0 0 0 55 0 0 0 0 0 60 0 2 2 3 9 65 0 0 1 1 2 75 0 0 0 0 0 34" Vertical Wall 50 mph or less 0 1 3 4 33 55 0 4 3 0 20 60 3 6 14 28 131 65 1 5 9 11 61 75 3 4 14 11 102 42" Vertical Wall 50 mph or less 0 0 0 0 1 55 0 3 3 2 11 60 0 0 0 1 1 65 0 0 2 2 7 75 0 1 0 0 6 32" NJ Shape 50 mph or less 0 2 4 2 46 55 0 2 1 4 19 60 0 2 4 6 36 65 0 0 4 2 19 75 1 0 1 0 14 42" NJ Shape 50 mph or less 0 0 1 3 4 55 0 1 2 6 20 60 2 0 3 9 14 65 0 0 1 0 1 75 0 0 0 0 0 Read the entire page →
From page 115... ... Probability of Crash Severity (PSEVj) C-7 Table C-3 Barrier Crash Data Assembled Under NCHRP Project 22-27 (Ray 2012) Read the entire page →
From page 116... ... C-8 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Table C-6 Washington Crash Data for Tree Crashes (after Ray 2012) Feature PSL K A B C O Unk Tree 70 5 7 30 20 103 8 Tree 65 1 1 2 0 7 0 Tree 60 10 26 86 93 200 34 Tree 55 21 32 112 87 168 35 Tree 50 12 23 75 52 151 29 Tree 45 1 3 19 20 44 10 Tree 40 3 11 21 18 56 9 Tree 35 1 4 26 32 89 26 Tree 30 0 2 4 9 39 9 Tree 25 0 1 4 6 20 5 Table C-7 Washington Crash Data for Waterbody Crashes (after Ray 2012) Read the entire page →
From page 117... ... Probability of Crash Severity (PSEVj) C-9 when the barrier is struck on the design-impact side. Read the entire page →
From page 118... ... C-10 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Right" listed as the First Harmful Event, and some instances had one of these entries in the EVENT SEQ1, followed by "Concrete Traffic Barrier," "Guardrail Face," or "Cable Barrier" in EVENT SEQ2, with one of the barrier types listed as the First Harmful Event. The COUNTY, ROUTE_NAME, BEG_LOG, and END_LOG fields were used to attach the barrier inventory database to the SV FOHE LB crashes. Read the entire page →
From page 119... ... Probability of Crash Severity (PSEVj) C-11 inventoried as "other." There were 28,141 SV FOHE LB crashes where the type of barrier involved could not be positively identified using the Ohio inventory. Read the entire page →
From page 120... ... C-12 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Table C-11 Ohio SV FOHE LB Crash Counts by Posted Speed Limit: Single Slope Barriers PSL K A B C O 65 0 1 3 5 54 60 0 0 2 2 5 55 0 1 2 3 8 50 0 0 0 0 3 45 0 0 0 0 0 40 0 0 0 0 0 35 0 0 0 0 0 30 0 0 0 0 0 25 0 0 0 0 0 Table C-12 Ohio SV FOHE LB Crash Counts by Posted Speed Limit: Unable to Associate with a Barrier Type PSL K A B C O 65 9 201 1513 1307 10270 60 11 120 634 813 4119 55 9 144 728 650 4544 50 5 35 173 205 933 45 0 14 49 36 427 40 0 4 26 20 142 35 0 17 94 82 652 30 0 0 3 0 2 25 1 6 14 10 119 Pennsylvania A total of 5,903 SV FOHE LB crashes were found during the 6-year study period in Pennsylvania. These LB crashes were then linked to the roadside hardware inventory for each identified longitudinal barrier. Read the entire page →
From page 121... ... Probability of Crash Severity (PSEVj) C-13 • Intermediate Bulk Container (IBC) Read the entire page →
From page 122... ... C-14 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers 25 0 0 0 0 2 1 20 0 0 0 0 0 0 15 0 0 0 0 0 0 Table C-14 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: Weak Post Cable PSL K A B C O Unk 70 0 0 0 0 0 0 65 0 0 0 0 0 0 60 0 0 0 0 0 0 55 0 0 1 1 27 0 50 0 0 0 0 0 0 45 0 0 0 0 0 0 40 0 0 0 0 0 0 35 0 0 0 0 0 0 30 0 0 0 0 0 0 25 0 0 0 0 0 0 20 0 0 0 0 0 0 15 0 0 0 0 0 0 Table C-15 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: Strong Post W-Beam with Rub Rail and Offset Bracket PSL K A B C O Unk 70 0 0 0 0 0 0 65 0 0 1 4 12 0 60 0 0 0 0 0 0 55 0 1 2 16 69 14 50 0 1 1 2 8 1 45 0 0 1 9 33 10 40 0 1 2 8 27 0 35 0 2 4 7 22 9 30 0 0 0 0 6 0 25 0 0 1 2 5 5 20 0 0 0 1 0 0 15 0 0 0 0 0 0 Read the entire page →
From page 123... ... Probability of Crash Severity (PSEVj) C-15 Table C-16 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: Strong Post W-Beam with Offset Bracket PSL K A B C O Unk 70 0 0 0 2 5 0 65 1 3 11 79 342 19 60 0 0 0 0 0 0 55 4 25 78 210 753 87 50 0 3 0 11 42 5 45 4 23 34 98 283 42 40 0 3 19 53 168 20 35 3 5 13 38 148 25 30 0 1 3 6 24 2 25 0 0 5 8 23 4 20 0 0 0 1 0 1 15 0 0 0 0 0 0 Table C-17 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: Strong Post W-Beam PSL K A B C O Unk 70 0 0 0 0 0 0 65 0 0 0 0 0 0 60 0 0 0 0 0 0 55 0 0 0 3 18 0 50 0 0 0 0 0 0 45 0 0 0 0 3 0 40 0 0 0 0 5 0 35 0 0 0 3 6 2 30 0 0 0 0 2 1 25 0 0 1 0 2 1 20 0 0 0 0 0 0 15 0 0 0 0 0 0 Read the entire page →
From page 124... ... C-16 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Table C-18 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: Weak Post W-Beam PSL K A B C O Unk 70 0 0 0 0 3 0 65 0 2 9 42 357 8 60 0 0 0 0 0 0 55 0 7 15 65 330 27 50 0 0 1 6 25 5 45 0 2 8 16 91 6 40 0 3 2 4 27 4 35 0 0 3 4 19 4 30 0 0 0 0 2 0 25 1 0 0 0 3 0 20 0 0 0 0 0 0 15 0 0 0 0 0 0 Table C-19 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: Strong Post W-Beam, Double-Faced PSL K A B C O Unk 70 0 0 0 0 0 0 65 0 0 0 0 0 0 60 0 0 0 0 0 0 55 0 2 2 11 32 7 50 0 0 0 1 1 0 45 0 0 1 1 2 1 40 0 0 0 1 5 0 35 0 0 2 2 2 1 30 0 0 0 0 0 0 25 0 0 0 0 0 0 20 0 0 0 0 0 0 15 0 0 0 0 0 0 Read the entire page →
From page 125... ... Probability of Crash Severity (PSEVj) C-17 Table C-20 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: Weak Post W-Beam, Double-Faced PSL K A B C O Unk 70 0 0 0 0 0 0 65 0 0 0 0 0 0 60 0 0 0 0 0 0 55 0 0 0 6 52 8 50 0 0 0 0 0 0 45 0 0 0 0 0 0 40 0 0 0 0 0 0 35 0 0 0 0 0 0 30 0 0 0 0 1 0 25 0 0 0 0 0 0 20 0 0 0 0 0 0 15 0 0 0 0 0 0 Table C-21 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: Weak Post Box Beam PSL K A B C O Unk 70 0 0 0 0 0 0 65 0 0 0 0 0 0 60 0 0 0 0 0 0 55 0 0 0 1 15 5 50 1 0 0 0 0 0 45 0 0 0 1 5 0 40 0 0 0 0 0 0 35 0 0 0 0 5 2 30 0 0 0 0 0 0 25 0 0 0 0 0 0 20 0 0 0 0 0 0 15 0 0 0 0 0 0 Read the entire page →
From page 126... ... C-18 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Table C-22 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: Concrete Safety Shape PSL K A B C O Unk 70 0 0 0 0 0 0 65 0 2 9 28 79 6 60 0 0 0 0 0 0 55 1 7 44 158 523 79 50 0 0 12 45 89 22 45 0 1 4 18 66 14 40 0 0 1 20 59 6 35 0 0 3 17 22 7 30 0 0 0 0 2 0 25 0 0 1 2 2 1 20 0 0 0 0 0 0 15 0 0 0 0 0 0 Table C-23 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: IBC Barrier PSL K A B C O Unk 70 0 0 0 0 0 0 65 0 0 0 4 14 1 60 0 0 0 0 0 0 55 0 0 0 1 4 1 50 0 0 0 0 0 0 45 0 0 0 0 0 0 40 0 0 0 0 0 0 35 0 0 0 0 0 0 30 0 0 0 0 0 0 25 0 0 0 0 0 0 20 0 0 0 0 0 0 15 0 0 0 0 0 0 Read the entire page →
From page 127... ... Probability of Crash Severity (PSEVj) C-19 Table C-24 Pennsylvania SV FOHE LB Crash Counts by Posted Speed Limit: Propriety Cable Systems (All Combined) Read the entire page →
From page 128... ... C-20 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers The severity distributions for each barrier type are shown in Tables C-26 through C-29. There were 124 reported SV FOHE LB crashes with the Jersey Barrier. Read the entire page →
From page 129... ... Probability of Crash Severity (PSEVj) C-21 Table C-28 Tennessee SV FOHE LB Crash Counts by Posted Speed Limit: Proprietary Cable Barrier (All Combined) Read the entire page →
From page 130... ... C-22 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers CHAPTER 4 ESTIMATE UNREPORTED CRASHES Crash reporting thresholds vary by state, with some states only requiring reports when there is an injury, while others require a monetary threshold to be exceeded. It has long been recognized that police-reported crash data underreport lower severity crashes. Read the entire page →
From page 131... ... Probability of Crash Severity (PSEVj) C-23 Table C-30 Maximum Likelihood Estimate of Injuries for Concrete Barrier Family State and Barrier Observed Crashes MLE % INJ MA 32" 154 45.45 PA 32" F-Shape 164 33.64 All 32" F-Shape 318 40.16 MA 42" F-Shape 34 41.05 PA 42" F-Shape 56 28.26 All 42" F-Shape 90 28.26 All F-Shape 408 38.24 NE 29" Vertical Wall 20 43.11 NE 34" Vertical Wall 471 17.93 NE 42" Vertical Wall 40 10.73 All Vertical Wall 531 17.57 OH Single Slope 89 14.28 WA 34" Single Slope 178 0.00 All Single Slope 267 14.28 TN Jersey 124 16.66 OH 32" Jersey 195 25.14 NE 32" Jersey 169 9.37 TX 32" TL4 Jersey MB 1,678 0.00 OH 42" Jersey 54 15.51 NE 42" Jersey 67 43.34 All 32" Jersey 2,042 9.38 All 42" Jersey 121 27.77 All Jersey 2,163 9.38 All Concrete 7,325 16.74 Read the entire page →
From page 132... ... C-24 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Table C-31 Maximum Likelihood Estimate of Injuries for Cable Barrier Family State and Barrier Observed Crashes MLE % INJ WA TL3 HT Cable 541 10.02 IA TL3 HT Cable 20 15.00 PA HT Cable 82 23.27 TN HT Cable 55 13.26 All HT Cable 698 10.32 WA TL3 LT Cable 594 6.65 AZ TL3 LT Cable 20 25.00 NC TL3 LT Cable 127 30.70 OR TL3 LT Cable 26 19.23 PA LT Cable 29 9.63 All LT Cable 796 6.65 All HT and LT Cable 1,494 8.62 Table C-32 Maximum Likelihood Estimate of Injuries for Beam Barrier Family State and Barrier Observed Crashes MLE % INJ PA Strong Post W-Beam w/Rub Rail and Offset Bracket 287 26.00 PA Strong Post W-Beam with Offset Bracket 2,737 20.65 PA Strong Post W-Beam 47 19.95 PA MB Strong Post W-Beam 74 38.79 All PA Strong Post W-Beam 3,145 20.97 OH W-Beam 3,052 18.22 TN W-Beam 72 6.89 PA Weak Post W-Beam 1,101 12.67 PA MB Weak Post W-Beam 67 12.69 All PA Weak Post W-Beam 1,168 12.67 All Strong Post W-Beam 6,269 10.77 PA Box Beam 35 6.65 All Weak and Strong Post W-Beam 7,437 9.85 Read the entire page →
From page 133... ... Probability of Crash Severity (PSEVj) C-25 Table C-33 Maximum Likelihood Estimate of Injuries for Non-Barrier Median Features State and Feature Observed Crashes MLE % INJ WA Cross-Median Crash 23,928 16.51 WA Rollover 7,439 51.87 WA Tree 1,922 30.90 WA Waterbody 144 21.55 Read the entire page →
From page 134... ... C-26 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers CHAPTER 5 DETERMINE P(KA\|C) Carrigan and Ray explained in "Practitioner's Guide to the Analysis of In-Service Performance Evaluation Data" the relationship between absolute risk, portions, percentages, and probability of crashes with roadside hardware. Read the entire page →
From page 135... ... Probability of Crash Severity (PSEVj) C-27 Table C-34 Published z-values for Normal Distribution (Carrigan 2016) Read the entire page →
From page 136... ... C-28 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Figure C-1 P(KA\|C) for concrete barrier family with 95% confidence intervals. Read the entire page →
From page 137... ... Probability of Crash Severity (PSEVj) C-29 Figure C-2 P(KA\|C) Read the entire page →
From page 138... ... C-30 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Figure C-3 P(KA\|C) for cable barrier family with 95% confidence intervals. Read the entire page →
From page 139... ... Probability of Crash Severity (PSEVj) C-31 Figure C-4 P(KA\|C) Read the entire page →
From page 140... ... C-32 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Figure C-5 P(KA\|C) for metal beam barrier family with 95% confidence intervals. Read the entire page →
From page 141... ... Probability of Crash Severity (PSEVj) C-33 One approach for providing P(KA\|C) Read the entire page →
From page 142... ... C-34 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers CHAPTER 6 RESULTS AND DISCUSSION The forgoing statistical analysis presented in this document provided the analysis and justification for each recommended grouping of barriers and features. Throughout the analysis, the 95% confidence intervals were presented to ensure high confidence in the recommended groupings. Read the entire page →
From page 143... ... Probability of Crash Severity (PSEVj) C-35 such as the guidelines being developed provides a systematic methodology based on observed data and established crash severity relationships. Read the entire page →
From page 144... ... C-36 Selection and Placement Guidelines for Test Level 2 Through Test Level 5 Median Barriers Ray, Malcolm H., Christine E Carrigan, and Chuck A Read the entire page →

From page 109...

... C-1 A P P E N D I X C Probability of Crash Severity (PSEVj) CONTENTS Chapter 1 Introduction Chapter 2 Method Chapter 3 Available Data Data from the Literature New Data Gathered Chapter 4 Estimate Unreported Crashes Chapter 5 Determine P(KA|C)