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Federal Highway Administration Research and Technology
Coordinating, Developing, and Delivering Highway Transportation Innovations

 
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Publication Number:  FHWA-HRT-13-088    Date:  May 2014
Publication Number: FHWA-HRT-13-088
Date: May 2014

 

Photographic Data Extraction Feasibility and Pilot Study in Support of Roadside Safety and Roadway Departure Research

 

APPENDIX C: COMPLETE SUMMARY STATISTICS

This appendix presents all the attributes found in the data extraction process, as seen in table 8 through table 25. Due to its completeness, this appendix presents only the number of attributes and their percentage for each of the variables. Some of these values were already presented in the “Descriptive Summary Statistics” section.

Table 8. Reported precipitation.

Attribute Count Percent
Liquid 63 16.3
Freezing 0 0.0
Frozen 20 5.2
None 278 71.8
Not reported 26 6.7

 

Table 9. Location of the first shoulder involved.

Attribute Count Percent
No shoulder involved 7 1.8
Left side of road 229 59.2
Right side of road 148 38.2
Other 3 0.8
Unknown 0 0.0

 

Table 10. Representative paved shoulder width.

Attribute Count Percent
No shoulder involved 8 2.1
No paved shoulder 21 5.4
Less than 4 ft 104 26.9
4 to 8 ft 98 25.3
More than 8 ft 140 36.2
Indistinguishable from photos 16 4.1
Unknown location of first shoulder involved 0 0.0

 

Table 11. Representative unpaved shoulder width.

Attribute Count Percent
No shoulder involved 8 2.1
No unpaved shoulder 285 73.6
Less than 4 ft 54 14.0
4 to 8 ft 13 3.4
More than 8 ft 13 3.4
Indistinguishable from photos 14 3.6
Unknown location of first shoulder involved 0 0.0

 

Table 12. Major variations in paved shoulder width.

Attribute Count Percent
No shoulder involved 9 2.3
No paved shoulder 19 4.9
Yes 39 10.1
No 303 78.3
Indistinguishable from photos or other sources 17 4.4
Unknown location of first shoulder involved 0 0.0

 

Table 13. Major variations in unpaved shoulder width.

Attribute Count Percent
No shoulder involved 8 2.1
No unpaved shoulder 274 70.8
Yes 34 8.8
No 53 13.7
Indistinguishable from photos or other sources 18 4.7
Unknown location of first shoulder involved 0 0.0

 

Table 14. Roadway to paved shoulder drop-off.

Attribute Count Percent
No shoulder involved 9 2.3
No paved shoulder 19 4.9
Yes 72 18.6
No 248 64.1
Indistinguishable from photos 39 10.1
Unknown location of first shoulder involved 0 0.0

 

Table 15. Presence of rumble strips.
Attribute Count Percent
No shoulder involved 7 1.8
No paved shoulder 15 3.9
Yes 76 19.6
No 260 67.2
Indistinguishable from photos 29 7.5
Unknown location of first shoulder involved 0 0.0

 

Table 16. Roadway pavement type.
Attribute Count Percent
Asphalt 268 69.3
Concrete 104 26.9
Other: specify 6 1.6
Indistinguishable from photos 9 2.3

 

Table 17. Pavement marking quality.
Attribute Count Percent
Visible 375 96.9
Decayed 8 2.1
Indistinguishable from photos 4 1.0

 

Table 18. Location of the first compromised barrier.
Attribute Count Percent
No barrier compromised 1 0.3
Left side of road 232 59.9
Right side of road 146 37.7
Other 8 2.1
Indistinguishable from photos 0 0.0
Unknown location 0 0.0

 

Table 19. Barrier type.
Attribute Count Percent
No barrier compromised 1 0.3
Aesthetic timber barrier/wood guardrail 1 0.3
Box beam 3 0.8
Bridge rail 0 0.0
Constant slope barrier (UK equivalent concrete step barrier) 1 0.3
F-shaped barrier 0 0.0
GM® barrier shape 2 0.5
High-tension cable guardrail systems 4 1.0
Impact attenuators 8 2.1
Jersey barrier 190 49.1
Low-tension cable guardrail 1 0.3
Median barrier steel guardrail 0 0.0
Median strip 1 0.3
Steel-backed timber guardrail 0 0.0
Temporary impact attenuators 0 0.0
Thrie beam 0 0.0
Thrie beam strong post 15 3.9
Water- and sand-filled barriers 1 0.3
W-beam strong post 127 32.8
W-beam weak post 6 6
Weak post box beam 0 0
Weathering steel (Corten®) guardrail 0 0
Other: specify 21 21
Indistinguishable from photos 5 5
Unknown location of first barrier compromised 0 0

 

Table 20. Barrier end treatment type.
Attribute Count Percent
Outside the road segment of analysis 270 69.8
Bull nose end treatment 2 0.5
Guardrail bridge attachment 8 2.1
Rock fence 0 0.0
Rounded terminal buffer (“question mark”) 14 3.6
SGT (SKT-350) types I, II, and III, HBA 21 5.4
TAS or “turndown” roll-over end section 3 0.8
Terminal end sections (boxing glove) 10 2.6
Thrie beam terminal connector shoe (“end shoe”) 1 0.3
Trail end guardrail sections 4 1.0
W-beam terminal connector shoe 2 0.5
Jersey barrier end treatment type F 4 1.0
Impact attenuators 11 2.8
Other 22 5.7
Indistinguishable from photos 15 3.9

 

Table 21. Barrier post material.
Attribute Count Percent
No barrier compromised 1 0.3
Wood 69 17.8
Metal 91 23.5
Indistinguishable from photos 9 2.3
Not applicable (i.e., Jersey barrier) 217 56.1
Unknown location of first barrier compromised 0 0.0

 

Table 22. Barrier block-out material.
Attribute Count Percent
No barrier compromised 2 0.5
Wood 83 21.4
Plastic 12 3.1
Metal 29 7.5
Indistinguishable from photos 29 7.5
No block-out material 7 1.8
Not applicable (i.e., Jersey barrier) 224 57.9
Unknown location of first barrier compromised 0 0.0
None 1 0.3

 

Table 23. Location of crash with respect to barrier.
Attribute Count Percent
Along the barrier 270 69.8
At the end of the barrier 116 30.0
No barrier involved 1 0.3

 

Table 24. Location of crash with respect to guardrail.
Attribute Count Percent
Along the guardrail 254 65.6
At the end of the guardrail 95 24.5
No guardrail involved 38 9.8

 

Table 25. Barrier condition.
Attribute Count Percent
No barrier compromised 2 0.5
No visible damage 23 5.9
Scuffing, scraping 174 45.0
Breakage, barrier face 74 19.1
Breakage, component 35 9.0
Compromised location 35 6.5
Indistinguishable from photos 54 14.0
Unknown location of first barrier compromised 0 0.0
Unknown since photos were taken before crash 0 0.0
Unknown since photos were taken more than 1 month after crash 0 0.0

 

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