Research Article
Investigation into Interactions between Accident Consequences and Traffic Signs: A Bayesian Bivariate Tobit Quantile Regression Approach
Table 2
Estimation results for Bayesian bivariate Tobit quantile/mean regression models.
| Variable | Quantile | Mean Regression | 0.25 | 0.50 | 0.75 | 0.90 | 0.95 |
| Accident Rate of MD | | | |
| Low visibility | 0.013 | 0.020 | 0.026 | 0.081 | 0.188 | 0.024 | (5.51) | (7.20) | (3.78) | (2.46) | (6.89) | (4.32) | Average speed limit | -0.005 | -0.007 | -0.016 | -0.019 | -0.037 | -0.009 | (-2.71) | (-3.51) | (-3.08) | (-0.78) | (-1.81) | (-1.72) | No. of mandatory signs | -0.002 | -0.004 | -0.004 | -0.009 | -0.010 | -0.001 | (-5.18) | (-7.17) | (-3.23) | (-1.96) | (-1.99) | (-5.16) | No. of invalid traffic signs per km | 0.006 | 0.015 | 0.028 | 0.065 | 0.048 | 0.155 | (2.60) | (5.49) | (4.28) | (2.06) | (1.87) | (6.18) | Constant | 0.586 | 0.832 | 1.397 | 1.474 | 3.215 | 0.808 | (4.66) | (5.67) | (3.96) | (0.86) | (2.28) | (2.16) |
| Accident Rate of DI | | |
| Low visibility | 0.007 | 0.015 | 0.032 | 0.093 | 0.183 | 0.019 | (4.15) | (5.48) | (5.62) | (2.67) | (6.95) | (4.88) | Average speed limit | -0.004 | -0.007 | -0.008 | -0.020 | -0.032 | -0.012 | (-3.11) | (-3.26) | (-1.98) | (-1.79) | (-1.56) | (-3.26) | No. of warning signs | -0.001 | -0.001 | -0.001 | -0.003 | -0.003 | -0.001 | (-3.45) | (-4.30) | (-3.55) | (-3.15) | (-2.55) | (-5.48) | No. of invalid traffic signs per km | 0.005 | 0.011 | 0.026 | 0.072 | 0.087 | 0.102 | (3.41) | (4.02) | (4.77) | (3.72) | (3.35) | (6.31) | Constant | 0.385 | 0.665 | 0.721 | 1.385 | 2.332 | 0.963 | (4.29) | (4.49) | (2.39) | (1.96) | (1.66) | (3.99) |
| Goodness-of-fit | | | | | |
| No. of Observations | 460 | | | | | | 1.123 | 0.982 | 0.973 | 0.984 | 1.128 | 1.137 | | 0.724 | 0.652 | 0.638 | 0.658 | 0.730 | 0.731 | Correlation | 0.758 | 0.766 | 0.791 | 0.764 | 0.753 | 0.765 | DIC | 1783.452 | 1635.683 | 1583.364 | 1642.538 | 1827.693 | 1858.634 |
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Significant at the 5% level. |