| | Other factor group 4 | | Layer | Topics | Rate |
| | Layer 1 | Alignment | Straight | 3% | | Inclination | Downhill, downhill less than 1%, downhill 1% to 3%, downhill 3% more, downhill less than 500 m, flat | 5% | | Cut and fill | Flatness, 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, 3/3, 2/4, 3/3, 4/4 | 15% | | Shoulder, accelerate lane | 3% |
| | Layer 3 | Traffic obstacle factors | Non-working section, normal, congestion | 18% | | Road environment | Dry, wet | 9% | | Main accident cause | Poor loading, object on roads | 3% |
| | Layer 4 | Accident type | Single accident, shoulder guardrail, rear-end, head-on | 3% | | Vehicle operation Just before the accident | Driving, others, Overactive handle | 11% | | Main accident type | Vehicle-vehicle, vehicle-structure, others | 9% |
| | Layer 5 | Day and night | Daytime, nighttime | 5% | | Weather | Sunny, rainy | 11% |
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