An Analysis of the Effects of Crash Factors and Precrash Actions on Side Impact Crashes at Unsignalized Intersections

Table 6

Random-parameter multinomial logit model of precrash actions for side impact crashes at T-junctions.

Y1 = precrash action (base: other behaviors)		Ran stop sign			Failed to yield at stop sign			Failed to yield at turn
Variables and description		β	ME	β	ME	β	ME
Constant		−2.349			0.386			−2.766
Urban	Yes				0.532		4.06%
Crash location	Open country				0.260		1.10%	0.495		1.46%
	Residential area				−0.045		−0.17%	0.117		0.35%
	Shopping center				0.564		3.00%	0.628		3.32%
Roadway condition	Dry							1.646		16.60%
	Wet							1.501		2.36%
Lighting condition	Daylight	−0.179		−0.43%
	Dark without lighting	−1.489		0.42%
	Dark with lighting	0.175		0.06%
Roadway geometry	Straight level road	1.578		3.66%	1.107		11.82%
	Straight road with grade	1.695		1.11%	1.018		2.56%
Turn lane present	Yes	−2.718	0.819	−0.01%	−0.479	0.819	−1.90%
No functioning traffic control	Yes	−2.027	2.003	−1.04%	−2.959	2.003	−11.45%	0.453		3.02%
At-fault driver_speeding	Yes				−4.840	4.588	−0.31%	−3.299		2.36%
At-fault driver_DUI	Yes	−0.894		−0.07%	−3.952		−0.40%	−2.146		−0.20%
Gender	Male	−0.696		1.53%
At-fault driver age	21 years old or younger				−0.082		−0.27%	−0.097		−0.26%
	22∼31 years old				−0.412		−1.17%	−0.203		−0.49%
	32∼41 years old				−0.558		−1.00%	−0.336		−0.49%
	42∼51 years old				−0.372		−0.58%	−0.187		−0.26%
	52∼61 years old				−0.444		−0.71%	−0.354		−0.45%
	62∼71 years old				−0.245		−0.33%	−0.105		−0.12%
Point of impact	Front passenger side	0.665		0.32%				−0.542		−0.33%
	Back passenger side	0.314		0.09%				−0.714		−0.29%
	Bumper	−0.168		−0.18%				0.820		5.55%
	Driver door	0.284		0.09%				0.173		0.18%
	Passenger side behind the driver	0.013		0.00%				0.067		0.06%
Causal vehicle type	Passenger car				0.248		1.82%
	Pickup				0.033		0.08%
	SUV				0.157		0.47%
Noncausal vehicle type	Passenger car	−0.454		−0.63%
	Pickup	−0.127		−0.09%
	SUV	−0.389		−0.23%
Scale parameters for random parameters in precrash actions	Dark without lighting	3.364
	Turn lane present	2.046
	Male	1.694
	Urban				1.876
Summary statistics	Number of observations	10,750
	Log likelihood at zero L (0)	−12,143.177
	Log likelihood at convergence L (β)	−10,184.482
	Pseudo-R2	0.161
	Likelihood-ratio test (vs. regular multinomial logit)	Prob. = 0.000
	AIC	20,485.0