| | Vehicle factor group 2 | | Layer | Topics | Rate |
| | Layer 1 | Alignment | Left-curve, left-curve 1000 m more, right-curve, right-curve 500 m–1000 m, right-curve 1000 m more, straight | 5% | | Inclination | Uphill, uphill less than 1%, uphill 1% to 3%, uphill 3% more, flat | 4% | | Cut and fill | Flatness, fill height less than 2 m, fill height 2 m–5 m, fill height 5 m–15 m, cut part less than 10 m, cut part 10 m more | 5% |
| | Layer 2 | Point of occurrence | Main lane | 1/2, 1/3, 1/4, 2/2, 2/3, 2/4, 3/3, 3/4, 3/5, 4/4, 4/5, 5/5 | 15% |
| | Layer 3 | Traffic obstacle factors | Non-working section, normal | 12% | | Road environment | Dry | 7% | | Main accident cause | Tire damage, Brake device defects, problem of device parts | 13% |
| | Layer 4 | Accident type | Single accident, rear-end, head-on | 3% | | Vehicle operation just before the accident | Driving, others | 9% | | Main accident type | Vehicle-vehicle, others | 7% |
| | Layer 5 | Day and night | Daytime, nighttime | 6% | | Weather | Sunny | 8% |
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