| 1 |
Lowest proportion of accidents with smoke and/or fog reported (130 of 127,604 accidents, or just over 0.0010 accidents.) |
| 2 |
Physical or statistical reasons for not including in category 1, but proportion of accidents not significantly higher. |
| 3 |
Higher proportion of accidents than category 1, by about 30% to 50%, but of marginal significance (1%-5%). |
| 4 |
Significantly higher than category 1, by a factor of 2. |
| 5 |
Significantly higher than category 1, by a factor of 3 to 10. |
| 6 |
Significantly higher than category 1, by a factor of 10 to 20. |
| 7 |
Significantly higher than category 1, by a factor of 20 to 40. |
| 8 |
Significantly higher than category 1, by a factor of 40 to 75. |
| 9 |
Significantly higher than category 1, by a factor of 75 to 125. |
| 10 |
Significantly higher than category 1, by a factor of 150. |