Table 4.

Model estimation results for car-strike-truck crashes (P2T).

Variable	Fixed Parameters Model		Random Parameters Model
	Coefficient	t-stat	Coefficient	t-stat
Constant	0.8122 ***	7.31	0.9972 ***	8.51
Person Characteristics
Male	−0.1750 ***	−4.09	−0.2793 ***	−6.33
• Standard deviation of parameter density function			0.5610 ***	19.62
Use of restraint system	−0.9796 ***	−11.49	−1.1135 ***	−12.34
Age under 25	−0.1603 ***	−3.49	−0.1780 ***	−3.76
Age above 64	0.2202 ***	2.91	0.2263 ***	2.92
Vehicle Characteristics
Truck	−0.8980 ***	−11.29	−1.0162 ***	−12.04
Vehicle with one or more trailing units	−0.6942 ***	−7.02	−0.8488 ***	−7.76
Driver drinking in vehicle	0.3776 ***	4.55	0.3941 ***	4.77
Roadway and Environment
Icy or snowy road surface	−0.2569 **	−2.34	−0.2676 **	−2.39
Dark	0.2127 ***	4.33	0.2387 ***	4.73
Dawn or dusk	0.3620 ***	3.26	0.3749 ***	3.19
Crash Mechanism
Going straight before crash	0.1314 **	2.26	0.1230 **	2.06
Starting/stopped in road before crash	−0.2948 ***	−3.31	−0.9347 ***	−6.62
• Standard deviation of parameter density function			1.0185 ***	9.83
Critical event-other vehicle stopped in lane	−0.3000 ***	−5.75	−0.3161 ***	−5.93
Critical event-other vehicle in lane traveling in same direction while decelerating	−0.3348 ***	−5.75	−0.3581 ***	−6.03
Temporal Characteristics
Weekdays	0.0863 **	1.97	0.1014 **	2.22
Spring	0.0790 *	1.78	0.0843 *	1.81
Thresholds
Mu(01)	0.5657 ***	29.25	0.6230 ***	27.91
Mu(02)	1.3332 ***	39.52	1.4623 ***	37.97
Number of observations	4866		4866
Restricted log likelihood	−4318.1191		−4318.1191
Log likelihood function	−3747.5979		−3737.4327
Akaike Information Criterion (AIC)	7533.2		7516.9

Note: ***, **, * refer to Significance at 1%, 5%, 10% level.