Bayesian Hierarchical Modeling Monthly Crash Counts on Freeway Segments with Temporal Correlation
Table 4
Model estimation results.
Poisson
Random effect
Autoregression-1
Random effect with autoregression-1
Constant
−10.25 (1.39)
−10.82 (2.19)
−10.4 (1.56)
−10.34 (2.39)
Length
1.04 (0.11)
1.00 (0.15)
1.02 (0.15)
0.99 (0.16)
MTT
0.35 (0.15)
0.42 (0.26)
0.37 (0.18)
0.41 (0.21)
0.08 (0.08)
0.11 (0.10)
0.10 (0.10)
0.08 (0.10)
−0.01 (0.02)
−0.003 (0.02)
−0.008 (0.02)
−0.01 (0.03)
−0.08 (0.05)
−0.09 (0.06)
−0.10 (0.06)
−0.11 (0.06)
Gradient
0.25 (0.07)
0.17 (0.09)
0.18 (0.09)
0.17 (0.09)
Curvature
0.06 (0.03)
0.04 (0.04)
0.04 (0.04)
0.04 (0.04)
Bridge
0.02 (0.08)
0.01 (0.11)
0.01 (0.10)
0.02 (0.10)
Access
0.07 (0.09)
0.03 (0.13)
0.04 (0.12)
0.04 (0.12)
—
0.39 (0.06)
—
0.27 (0.12)
—
—
0.72 (0.14)
0.46 (0.23)
—
—
0.37 (0.13)
0.37 (0.14)
2883
2790
2682
2683
pD
10
65
155
155
DIC
2893
2854
2837
2838
Estimated mean (standard deviation) for the parameter; significant at the 95% credible level; significant at the 90% credible level; significant at the 80% credible level.
