U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
202-366-4000
FHWA Review of ET-Plus
This summary presents FHWA's observations of the crash cases contained in the spreadsheet and supporting documentation provided by the source. FHWA received a spreadsheet summarizing crash cases from 231 locations, by State, in which the source indicated a 4-inch ET-Plus guardrail terminal failed to operate as intended. These cases included photographs of damaged terminals, photographs of damaged vehicles involved in crashes, and additional documentation such as crash reports, new articles, and legal documents. FHWA reviewed each crash case using the documentation provided by the source to independently assess whether an ET-Plus 4-inch device was involved.
Of the 231 crash cases, FHWA's assessment is that 156 involved an ET-Plus 4-inch device. In addition, FHWA identified 29 initial crash cases of significant interest for further analysis that involved severe injuries, vehicle compartment intrusion, vehicle occupant compartment penetration, spearing, rollover, snagging of rail, or otherwise appeared to be unusual or extreme.
The tables in this Appendix provide frequency totals comparing the spreadsheet of the 231 crash cases and FHWA's analysis of those cases; a review of the 156 identified and confirmed ET-Plus 4-inch crash cases; and a review of the 29 crash cases for further analysis. The tables summarize whether an ET-Plus 4-inch device was involved in the crash; whether the result of the crash involved a fatality, injury or was unknown; and what supporting documentation was provided for each crash case to include media information, crash reports, legal documentation, photographs of the damaged device, photographs of the damaged vehicles, and photographs of new or replacement devices following a crash.
Table 1 summarizes the distribution of crash cases by State. Of the 231 crash cases, 70 percent (161) are from three States: Tennessee, Texas, and Virginia.
TABLE 1 – Number of Crash Cases by State
STATE | # OF CASES | % OF TOTAL | STATE | # OF CASES | % OF TOTAL | |
Alabama | 4 | 1.7% | New York | 1 | 0.4% | |
Arkansas | 3 | 1.3% | North Carolina | 5 | 2.2% | |
California | 5 | 2.2% | Ohio | 3 | 1.3% | |
Colorado | 1 | 0.4% | Oklahoma | 4 | 1.7% | |
Delaware | 1 | 0.4% | Oregon | 1 | 0.4% | |
Florida | 2 | 0.9% | Pennsylvania | 5 | 2.2% | |
Georgia | 3 | 1.3% | Rhode Island | 1 | 0.4% | |
Illinois | 5 | 2.2% | South Carolina | 3 | 1.3% | |
Kentucky | 1 | 0.4% | Tennessee | 75 | 32.5% | |
Maryland | 7 | 3.0% | Texas | 47 | 20.3% | |
Massachusetts | 2 | 0.9% | Vermont | 1 | 0.4% | |
Minnesota | 1 | 0.4% | Virginia | 39 | 16.9% | |
Missouri | 5 | 2.2% | West Virginia | 2 | 0.9% | |
New Hampshire | 3 | 1.3% | ||||
New Jersey | 1 | 0.4% | Total | 231 | 100.0% |
Table 2 summarizes the results of FHWA's independent review of the crash cases contained in the spreadsheet. FHWA reviewed the photographs for each crash case to determine whether the device had a 4-inch channel width and the head was visible. Photographs that clearly displayed a 4-inch channel width and visible head were confirmed by FHWA to be an ET-Plus 4-inch device. Conversely, photographs that clearly confirmed that the device was not an ET-Plus 4-inch (i.e., ET-Plus 5-inch or SKT) were classified as not being an ET-Plus 4-inch device. Photographs that did not clearly display the channel width or head were classified as unknown since FHWA was unable to make a determination regarding whether the device was an ET-Plus 4-inch. In addition, any crash cases that did not include photographs were also classified as unknown.
TABLE 2 – FHWA Review and Identification of ET-Plus 4-Inch Devices
FHWA OBSERVATIONS | FREQUENCY | % OF TOTAL |
Confirmed ET-Plus 4-inch device | 156* | 67.5% |
Non-ET-Plus 4-inch device (i.e., ET-Plus 5-inch or SKT) | 6 | 2.6% |
Unknown device | 69 | 29.9% |
Total | 231 | 100.0% |
* Note: More information about the 156 crash cases confirmed to be the ET-Plus 4-inch devices is provided in Tables 7 and 8.
Tables 3 and 4 summarize the severity of the 231 crash cases. In the source documents, the crash cases were categorized in the spreadsheet as a fatality/injury (fatalities and injuries were grouped together), no fatality/injury, or unknown. FHWA was able to further classify the cases as fatality or injury or unknown based on the documentation provided. In cases where there was no supporting documentation regarding the severity of the crash, FHWA identified those crashes as unknown. Table 3 shows the source's identification of the crash cases in the spreadsheet compared to FHWA's analysis identifying crash severity, and Table 4 shows a comparison of the crash cases.
TABLE 3 – Source Identification of Crash Severity
CRASH SEVERITY | Source OBSERVATIONS (Spreadsheet) |
% OF TOTAL | FHWA OBSERVATIONS |
% OF TOTAL |
Fatality | 52 | 22.5% | 19 | 8.2% |
Injury | 20 | 8.7% | ||
No Fatality/Injury | 1 | 0.4% | 0 | 0.0% |
Unknown | 178 | 77.1% | 192 | 83.1% |
Total | 231 | 100.0% | 231 | 100.0% |
TABLE 4 – Comparison of Crash Severity
SOURCE (Spreadsheet) OBSERVATION |
FHWA OBSERVATION |
FREQUENCY | % OF TOTAL |
Fatality/Injury | Fatality | 18 | 7.8% |
Injury | 20 | 8.7% | |
Fatality/Injury | Unknown | 14 | 6.1% |
No Fatality/Injury | Unknown | 1 | 0.4% |
Unknown | Fatality | 1 | 0.4% |
Unknown | Unknown | 177 | 76.6% |
Total | 231 | 100.0% |
Table 5 provides a summary of the types of documentation provided. FHWA reviewed all of the crash cases to identify the documentation that was provided for each case.
TABLE 5 – FHWA Review of Supporting Documentation
FHWA Observation |
Media Information |
Crash Report |
Legal Documents |
Photo of Damaged Device |
Photo of Vehicle |
Photo of New or Replacement Installation |
Included in case files | 23 (10.0%) |
10 (4.3%) |
6 (2.6%) |
211 (91.3%) |
35 (15.2%) |
2 (0.9%) |
Not included in case files | 208 (90.0%) |
221 (95.7%) |
225 (97.4%) |
20 (8.7%) |
196 (84.8%) |
229 (99.1%) |
Total | 231 | 231 | 231 | 231 | 231 | 231 |
Confirmed ET-Plus 4-Inch Crash Cases
FHWA confirmed a total of 156 crash cases to involve an ET-Plus 4-inch device summarized below using the same criteria as in Tables 1, 3, 4 and 5.
TABLE 6 – Number of Crashes by State of Confirmed ET-Plus 4-Inch Crash Cases from Source Document
STATE | # OF CASES | % OF TOTAL | STATE | # OF CASES | % OF TOTAL | |
Alabama | 3 | 1.9% | New York | 1 | 0.6% | |
Arkansas | 2 | 1.3% | North Carolina | 2 | 1.3% | |
California | 1 | 0.6% | Ohio | 2 | 1.3% | |
Colorado | 0 | 0.0% | Oklahoma | 3 | 1.9% | |
Delaware | 1 | 0.6% | Oregon | 0 | 0.0% | |
Florida | 1 | 0.6% | Pennsylvania | 4 | 2.6% | |
Georgia | 3 | 1.9% | Rhode Island | 1 | 0.6% | |
Illinois | 3 | 1.9% | South Carolina | 2 | 1.3% | |
Kentucky | 0 | 0.0% | Tennessee | 62 | 39.7% | |
Maryland | 6 | 3.9% | Texas | 24 | 15.6% | |
Massachusetts | 1 | 0.6% | Vermont | 0 | 0.0% | |
Minnesota | 0 | 0.0% | Virginia | 28 | 18.2% | |
Missouri | 3 | 1.9% | West Virginia | 1 | 0.6% | |
New Hampshire | 2 | 1.3% | ||||
New Jersey | 0 | 0.0% | Total | 156 | 100.0% |
TABLE 7 – FHWA Identification of Crash Severity of Confirmed ET-Plus 4-Inch Crash Cases
CRASH SEVERITY |
SOURCE |
% OF TOTAL |
FHWA |
% OF TOTAL |
Fatality |
13 |
8.3% |
5 |
3.2% |
Injury |
4 |
2.6% |
||
Unknown |
143 |
91.7% |
147 |
94.2% |
Total |
156 |
100.0% |
156 |
100.0% |
TABLE 8 – Comparison of Crash Severity of Confirmed ET-Plus 4-Inch Crash Cases
SPREADSHEET |
FHWA |
FREQUENCY |
% OF TOTAL |
Fatality/Injury |
Fatality |
5 |
3.2% |
Injury |
4 |
2.6% |
|
Fatality/Injury |
Unknown |
4 |
2.6% |
Unknown |
Unknown |
143 |
91.7% |
Total |
156 |
100.0% |
TABLE 9 – Supporting Documentation for Confirmed ET-Plus 4-Inch Crash Cases
FHWA Observation |
Media Information |
Crash Report |
Legal Documents |
Photo of Damaged Device |
Photo of Vehicle |
Photo of New or Replacement Installation |
# Included in case files | 4 (2.6%) |
2 (1.3%) |
1 (0.6%) |
153 (98.1%) |
9
(5.8%) |
2 (1.3%) |
# Not included in case files | 152 (97.4%) |
154 (98.7%) |
155 (99.4%) |
3 (1.9%) |
147 (94.2%) |
154 (98.7%) |
Total | 156 | 156 | 156 | 156 | 156 | 156 |
29 Crash Cases Analyzed Further
Tables 10 through 14 present information regarding the 29 crash cases from the source, which the Task Force analyzed to attempt to assess the performance of the 4-inch ET-Plus. They represent cases of interest involving fatal or severe injury, vehicle occupant compartment intrusion, vehicle occupant compartment penetration, rollover, snagging of rail, or otherwise appeared to be unusual or extreme. These cases are summarized below using the same criteria that was used in Tables 1, 3, 4 and 5.
TABLE 10 – Number of Cases by States for the 29 Initial Crash Cases of Interest
STATE | # OF CASES | % OF TOTAL |
California | 2 | 6.9% |
Florida | 1 | 3.4% |
Illinois | 2 | 6.9% |
Massachusetts | 1 | 3.4% |
Minnesota | 1 | 3.4% |
Missouri | 1 | 3.4% |
New Hampshire | 1 | 3.4% |
North Carolina | 4 | 13.8% |
Ohio | 1 | 3.4% |
Oklahoma | 1 | 3.4% |
Oregon | 1 | 3.4% |
Pennsylvania | 4 | 13.8% |
South Carolina | 1 | 3.4% |
Tennessee | 4 | 13.8% |
Texas | 2 | 6.9% |
Virginia | 2 | 6.9% |
Total | 29 | 100.0% |
TABLE 11 – FHWA Review and Identification of the ET-Plus 4-Inch for 29 Cases
FHWA OBSERVATIONS | FREQUENCY | % OF TOTAL |
Confirmed ET-Plus 4-inch device | 13 | 44.8% |
ET-Plus 4-inch or 5-inch device | 1 | 3.4% |
Unknown device | 15 | 51.7% |
Total | 29 | 100.0% |
TABLE 12 – Independent Observations of Crash Severity for the 29 Crash Cases of Interest
OBSERVATIONS | SOURCE DOCUMENT (Spreadsheet) |
% OF TOTAL | FHWA | % OF TOTAL |
Fatality | 22 | 82.8% | 7 | 24.1% |
Injury | 14 | 48.3% | ||
No Fatality/Injury | 1 | 3.4% | 0 | 0.0% |
Unknown | 4 | 13.8% | 8 | 27.6% |
Total | 29 | 100.0% | 29 | 100.0% |
Table 13 – Comparison of Crash Severity for the 29 Crash Cases of Interest
SOURCE DOCUMENT (Spreadsheet) OBSERVATON |
FHWA OBSERVATION |
FREQUENCY | % OF TOTAL |
Fatality/Injury | Fatality | 7 | 24.1% |
Injury | 14 | 48.3% | |
Fatality/Injury | Unknown | 3 | 10.3% |
No Fatality/Injury | Unknown | 1 | 3.4% |
Unknown | Unknown | 4 | 13.8% |
Total | 29 | 100.0% |
Table 14 - FHWA Observations of Supporting Documentation for the 29 Crash Cases of Interest
FHWA Observation |
Media Information |
Crash Report |
Legal Documents |
Photo of Damaged Device |
Photo of Vehicle |
Photo of New or Replacement Installation |
# Included in case files | 11 (37.9%) |
5 (17.2%) |
3 (10.3%) |
23 (79.3%) |
16 (55.2%) |
0 (0.0%) |
# Not included in case files | 18 (62.1%) |
24 (82.8%) |
26 (89.7%) |
6 (20.7%) |
13 (44.8%) |
29 (100.0%) |
Total | 29 | 29 | 29 | 29 | 29 | 29 |
Summary
The majority of the 231 cases (177 cases or 77%) provided in the source document include only photos of a damaged device, the date the photos were taken, and the route location of where the damage occurred.
Due to the lack of complete information, FHWA could only confirm that the ET-Plus 4-inch device was involved in 156 cases (or 68% of the cases) with the greatest number of cases in Tennessee (62 or 40%). Based on FHWA's observations, 5 fatal crashes and 4 injury crashes (out of the 156 cases) were confirmed involving an ET-Plus 4-inch device.
Of the 231 cases, FHWA analyzed the 29 cases as presented in Tables 10 through 14. These crashes were identified for further analysis because they involved severe injury, vehicle compartment intrusion, spearing of the vehicle, vehicle occupant compartment penetration, rollover, snagging of rail, or otherwise appeared to be unusual or extreme conditions. FHWA's assessment was that 13 of these cases (4 fatal crashes, 4 injury crashes, and 5 of unknown severity) involved the ET-Plus 4-inch.
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