| Variable | No injury accidents | Injury or fatal accidents | ||
| Parameter | t-statistic | Parameter | t-statistic | |
| Zero-inflated Poisson (ZIP) model. Poisson part | ||||
| Constant | 0.8001 | 8.32 | −0.559 | −1.62 |
| Passenger car volume | 0.00022 | 10.80 | −0.00012 | −1.53 |
| Heavy vehicle volume | 0.00014 | 3.57 | −0.00015 | −0.86 |
| Light non-passenger car vehicle volume | 0.00041 | 10.84 | 0.00076 | 5.48 |
| Traffic speed | 0.00392 | 5.04 | 0.0021 | 0.56 |
| Number of lanes | 0.1012 | 4.34 | −0.0008 | −0.02 |
| Number of horizontal curves | 0.2317 | 15.30 | 0.5012 | 11.88 |
| Number of access roads | 0.0939 | 12.73 | 0.1075 | 3.59 |
| Zero-inflated Negative binomial (ZINB) model. NB part | ||||
| Constant | 0.2718 | 0.78 | −1.2654 | −4.15 |
| Passenger car volume | 0.00028 | 4.12 | −0.00012 | −1.42 |
| Heavy vehicle volume | 0.00009 | 0.67 | −0.00017 | −1.32 |
| Light non-passenger car vehicle volume | 0.00064 | 5.09 | 0.0011 | 7.17 |
| Traffic speed | 0.0084 | 3.84 | 0.0130 | 4.42 |
| Number of lanes | 0.0569 | 0.90 | -0.0991 | −1.31 |
| Number of horizontal curves | 0.3031 | 6.51 | 0.4467 | 8.69 |
| Number of access roads | 0.1170 | 5.33 | 0.0656 | 2.41 |
| Dispersion parameter | 0.7650 | 13.12 | 0.6535 | 7.14 |