No. | Road parameters | Accident Modification Factors (AMF) | Where |
1 | Lane Width |
| AMFra = AMF of related accidents, Pra = proportion of related accidents, w & t indicate width & types of shoulder respectively |
2 | Shoulder Width |
| |
3 | Horizontal Curves (HC) |
| Lc = HC length (mi), S = spiral curve and R = HC radius (ft) |
4 | Super elevation | for ; for ; for | SV = super elevation variation (m/m) |
5 | Grades | G ≤ 3%, AMF5 = 1.00; 3% < G ≤ 6%, AMF5 = 1.10; and G > 6%, AMF5 = 1.16 | G = grade of the road |
6 | Driveway Density |
| DD = driveway density |
7 | Roadside Design |
| RHR = road hazard rating |
8 | Passing Lanes | AMF8 for short four-lane sections = 0.65 | AMF8 applied only for short four-lane section |