Rural Public Transportation Technologies: User Needs and Applications FR1-798
APPENDIX B
ACCIDENT SEVERITY DISTRIBUTIONS BY RAMP SEGMENT TYPE
FOR EIGHT SELECTED RAMP TYPES
This appendix presents accident severity distributions (fatal, injury, and
property-damage-only accidents) by ramp segment type for the following
eight selected ramp types in tables 48 through 55, respectively:
- Rural diamond off-ramps.
- Rural diamond on-ramps.
- Urban diamond off-ramps.
- Urban parclo loop off-ramps.
- Urban free-flow loop off-ramps.
- Urban outer connection off-ramps.
- Urban direct and semi-direct connection ramps.
- Urban C/D roads.
Table 48. Accident Severity Distribution by Ramp Segment Type for Rural
Diamond Off-Ramps (1993 Through 1995)
Ramp segment type |
Total length (mi) |
Number and percentage of accidents by severity level |
Fatal |
Injury |
Property damage only |
Total |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Normal deceleration lane
Deceleration lane with mainline lane drop
Ramp proper
Normal acceleration lane
Acceleration lane with mainline lane addition
Mainline weaving area
Diverge area on ramp
Merge area on ramp
Weaving area on ramp
Two-way roadway on ramp
Cross-road ramp terminal
(stop condition)
Cross-road ramp terminal
(free-flow)
Frontage road connection |
20.4 0.3 70.6 0.0 0.0 0.0 0.0 0.0 0.0 0.0 - - - |
0 0 2 - - - - - - - 1 0 0 |
0.0 0.0 0.6 - - - - - - - 0.3 0.0 0.0 |
6 1 64 - - - - - - - 60 0 0 |
1.8 0.3 18.9 - - - - - - - 17.7 0.0 0.0 |
15 0 96 - - - - - - - 94 0 0 |
4.4 0.0 28.3 - - - - - - - 27.7 0.0 0.0 |
21 1 162 - - - - - - - 155 0 0 |
6.2 0.3 47.8 - - - - - - - 45.7 0.0 0.0 |
Total |
91.3 |
3 |
0.9 |
131 |
38.6 |
205 |
60.5 |
339 |
100.0 |
Conversion: 1 mi = 1.61 km
Table 49. Accident Severity Distribution by Ramp Segment Type for Rural
Diamond On-Ramps (1993 Through 1995)
Ramp segment type |
Total length (mi) |
Number and percentage of accidents by severity level |
Fatal |
Injury |
Property damage only |
Total |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Normal deceleration lane
Deceleration lane with mainline lane drop
Ramp proper
Normal acceleration lane
Acceleration lane with mainline lane addition
Mainline weaving area
Diverge area on ramp
Merge area on ramp
Weaving area on ramp
Two-way roadway on ramp
Cross-road ramp terminal
(stop condition)
Cross-road ramp terminal
(free-flow)
Frontage road connection |
0.0 0.0 36.6 47.8 0.4 0.0 0.0 0.0 0.0 0.0 - - - |
- - 0 1 0 - - - - - 0 0 0 |
- - 0.0 0.7 0.0 - - - - - 0.0 0.0 0.0 |
- - 2 24 0 - - - - - 29 0 0 |
- - 1.4 16.8 0.0 - - - - - 20.3 0.0 0.0 |
- - 8 44 0 - - - - - 35 0 0 |
- - 5.6 30.8 0.0 - - - - - 24.5 0.0 0.0 |
- - 10 69 0 - - - - - 64 0 0 |
- - 7.0 48.3 0.0 - - - - - 44.8 0.0 0.0 |
Total |
84.8 |
1 |
0.7 |
55 |
38.5 |
87 |
60.8 |
143 |
100.0 |
Conversion: 1 mi = 1.61 km
Table 50. Accident Severity Distribution by Ramp Segment Type for Urban Diamond Off-Ramps (1993 Through 1995)
Ramp segment type |
Total length (mi) |
Number and percentage of accidents by severity level |
Fatal |
Injury |
Property damage only |
Total |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Normal deceleration lane
Deceleration lane with mainline lane drop
Ramp proper
Normal acceleration lane
Acceleration lane with mainline lane addition
Mainline weaving area
Diverge area on ramp
Merge area on ramp
Weaving area on ramp
Two-way roadway on ramp
Cross-road ramp terminal
(stop condition)
Cross-road ramp terminal
(free-flow)
Frontage road connection |
13.7 1.2 32.7 0.0 0.0 0.0 0.0 0.0 0.0 0.0 - - - |
0 0 4 - - - 0 - - - 0 0 0 |
0.0 0.0 0.2 - - - 0.0 - - - 0.0 0.0 0.0 |
64 20 372 - - - 0 - - - 334 3 0 |
3.7 1.2 21.6 - - - 0.0 - - - 19.4 0.2 0.0 |
66 23 447 - - - 2 - - - 383 1 0 |
3.8 1.3 26.0 - - - 0.1 - - - 22.3 0.1 0.0 |
130 43 823 - - - 2 - - - 717 4 0 |
7.6 2.5 47.9 - - - 0.1 - - - 41.7 0.2 0.0 |
Total |
47.6 |
4 |
0.2 |
793 |
46.1 |
922 |
53.6 |
1,719 |
100.0 |
Conversion: 1 mi = 1.61 km
Table 51. Accident Severity Distribution by Ramp Segment Type for Urban Parclo Loop Off-Ramps (1993 Through 1995)
Ramp segment type |
Total length (mi) |
Number and percentage of accidents by severity level |
Fatal |
Injury |
Property damage only |
Total |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Normal deceleration lane
Deceleration lane with mainline lane drop
Ramp proper
Normal acceleration lane
Acceleration lane with mainline lane addition
Mainline weaving area
Diverge area on ramp
Merge area on ramp
Weaving area on ramp
Two-way roadway on ramp
Cross-road ramp terminal
(stop condition)
Cross-road ramp terminal
(free-flow)
Frontage road connection |
0.4 0.0 0.8 0.0 0.0 0.1 0.0 0.0 0.0 0.6 - - - |
0 - 0 - - - 0 - - 0 0 0 0 |
0.0 - 0.0 - - - 0.0 - - 0.0 0.0 0.0 0.0 |
64 4 - 18 - - 0 - - 5 29 0 0 |
3.7 16.5 21.6 - - - 0.0 - - 4.6 26.6 0.0 0.0 |
3 -3 14 - - - 2 - - 6 30 0 0 |
2.8 - 12.8 - - - 0.1 - - 5.5 27.5 0.0 0.0 |
7 - 32 - - - 2 - - 11 59 0 0 |
6.4 - 29.4 - - - 0.1 - - 10.1 54.1 0.0 0.0 |
Total |
1.9 |
0 |
0.0 |
56 |
51.4 |
53 |
48.6 |
109 |
100.0 |
Conversion: 1 mi = 1.61 km
Table 52. Accident Severity Distribution by Ramp Segment Type for Urban Free-Flow Loop Off-Ramps (1993 Through 1995)
Ramp segment type |
Total length (mi) |
Number and percentage of accidents by severity level |
Fatal |
Injury |
Property damage only |
Total |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Normal deceleration lane
Deceleration lane with mainline lane drop
Ramp proper
Normal acceleration lane
Acceleration lane with mainline lane addition
Mainline weaving area
Diverge area on ramp
Merge area on ramp
Weaving area on ramp
Two-way roadway on ramp
Cross-road ramp terminal
(stop condition)
Cross-road ramp terminal
(free-flow)
Frontage road connection |
0.9 0.1 6.8 0.8 0.0 0.2 0.0 0.0 0.0 0.2 - - - |
0 0 1 0 - 0 0 - - 0 0 0 0 |
0.0 0.0 0.4 0.0 - 0.0 0.0 - - 0.0 0.0 0.0 0.0 |
8 0 53 9 - 3 0 - - 5 0 59 0 |
2.8 0.0 18.7 3.2 - 1.1 0.0 - - 1.8 0.0 20.8 0.0 |
8 0 53 9 - 3 0 - - 5 0 59 0 |
2.8 0.0 24.6 3.2 - 2.8 0.4 - - 2.8 0.0 14.8 0.0 |
16 0 124 18 - 11 1 - - 13 0 101 0 |
5.6 0.0 43.7 6.3 - 3.9 0.4 - - 4.6 0.0 35.6 0.0 |
Total |
9.0 |
1 |
0.4 |
137 |
48.2 |
146 |
51.4 |
284 |
100.0 |
Conversion: 1 mi = 1.61 km
Table 53. Accident Severity Distribution by Ramp Segment Type for Urban Outer Connection Off-Ramps (1993 Through 1995)
Ramp segment type |
Total length (mi) |
Number and percentage of accidents by severity level |
Fatal |
Injury |
Property damage only |
Total |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Normal deceleration lane
Deceleration lane with mainline lane drop
Ramp proper
Normal acceleration lane
Acceleration lane with mainline lane addition
Mainline weaving area
Diverge area on ramp
Merge area on ramp
Weaving area on ramp
Two-way roadway on ramp
Cross-road ramp terminal
(stop condition)
Cross-road ramp terminal
(free-flow)
Frontage road connection |
3.0 0.1 9.9 1.1 0.1 0.0 0.0 0.0 0.0 1.8 - - - |
0 0 1 0 0 - 0 - - 0 0 0 0 |
0.0 0.0 0.1 0.0 0.0 - 0.0 - - 0.0 0.0 0.0 0.0 |
11 0 148 4 2 - 5 - - 23 61 77 0 |
1.6 0.0 21.2 0.6 0.3 - 0.7 - - 3.3 8.8 11.0 0.0 |
13 0 185 3 4 - 5 - - 18 70 67 0 |
1.9 0.0 26.5 0.4 0.6 - 0.7 - - 2.6 10.0 9.6 0.0 |
24 0 334 7 6 - 10 - - 18 70 67 0 |
3.4 0.0 47.9 1.0 0.9 - 1.4 - - 5.9 18.8 20.7 0.0 |
Total |
16.0 |
1 |
0.1 |
331 |
47.5 |
365 |
52.4 |
697 |
100.0 |
Conversion: 1 mi = 1.61 km
Table 54. Accident Severity Distribution by Ramp Segment Type for Urban Direct and Semi-Direct Connection Ramps (1993 Through 1995)
Ramp segment type |
Total length (mi) |
Number and percentage of accidents by severity level |
Fatal |
Injury |
Property damage only |
Total |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Normal deceleration lane
Deceleration lane with mainline lane drop
Ramp proper
Normal acceleration lane
Acceleration lane with mainline lane addition
Mainline weaving area
Diverge area on ramp
Merge area on ramp
Weaving area on ramp
Two-way roadway on ramp
Cross-road ramp terminal
(stop condition)
Cross-road ramp terminal
(free-flow)
Frontage road connection |
3.5 1.4 16.5 7.6 2.4 0.2 1.3 1.9 0.0 0.0 - - - |
0 0 0 0 0 0 1 0 - - 0 0 0 |
0.0 0.0 0.0 0.0 0.0 0.0 0.2 0.0 - - 0.0 0.0 0.0 |
11 3 138 43 6 0 19 20 - - 2 16 0 |
2.0 0.5 25.2 7.9 1.1 0.0 3.5 3.7 - - 0.4 2.9 0.0 |
18 6 167 28 15 2 21 13 - - 4 14 0 |
3.3 1.1 30.5 5.1 2.7 0.4 3.8 2.4 - - 0.7 2.6 0.0 |
29 9 305 71 21 2 41 33 - - 6 30 0 |
5.3 1.6 55.8 13.0 3.8 0.4 7.5 6.0 - - 1.1 5.5 0.0 |
Total |
34.8 |
1 |
0.2 |
258 |
47.2 |
288 |
52.7 |
547 |
100.0 |
Conversion: 1 mi = 1.61 km
Table 55. Accident Severity Distribution by Ramp Segment Type for Urban C/D Roads (1993 Through 1995)
Ramp segment type |
Total length (mi) |
Number and percentage of accidents by severity level |
Fatal |
Injury |
Property damage only |
Total |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Frequency |
(%) |
Normal deceleration lane
Deceleration lane with mainline lane drop
Ramp proper
Normal acceleration lane
Acceleration lane with mainline lane addition
Mainline weaving area
Diverge area on ramp
Merge area on ramp
Weaving area on ramp
Two-way roadway on ramp
Cross-road ramp terminal
(stop condition)
Cross-road ramp terminal
(free-flow)
Frontage road connection |
3.4 1.1 10.9 7.9 1.7 0.0 3.0 2.0 3.3 0.0 - - - |
0 0 3 0 0 - 0 0 0 - 0 0 0 |
0.0 0.0 0.3 0.0 0.0 - 0.0 0.0 0.0 - 0.0 0.0 0.0 |
5 2 280 11 2 - 80 0 55 - 0 0 0 |
0.6 0.2 31.3 1.2 0.2 - 8.9 0.0 6.1 - 0.0 0.0 0.0 |
9 4 275 19 7 - 67 0 76 - 0 0 0 |
1.0 0.4 30.7 2.1 0.8 - 7.5 0.0 8.5 - 0.0 0.0 0.0 |
14 6 558 30 9 - 147 0 131 - 0 0 0 |
1.6 0.7 62.3 3.4 1.0 - 16.4 0.0 14.6 - 0.0 0.0 0.0 |
Total |
33.3 |
3 |
0.3 |
435 |
48.6 |
457 |
51.1 |
895 |
100.0 |
Conversion: 1 mi = 1.61 km
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