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:
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 Urbanl
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 Urbanl
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 Urbanl
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
U.S. DOT FHWA
Turner-Fairbanks Highway Research Center