Investigating the Differences of Single-Vehicle and Multivehicle Accident Probability Using Mixed Logit Model

Table 1

Descriptive statistics of response and significant explanatory variables.

Variable	Mean	Std. dev.	Minimum	Maximum
Crash type	0.008	0.121	0	2
Temporal characteristic
Night	0.431	na	0	1
Weekend	0.271	na	0	1
November	0.095	na	0	1
Time of sunset	0.062	na	0	1
4 a.m.-5 a.m.	0.040	na	0	1
Traffic characteristic
Low speed limit indicator (1 if speed limit is less than 55 miles per hour, 0 otherwise)	0.369	na	0	1
Speed gap (speed limit minus traffic speed) (mph)	2.642	5.533	0	69.18
Hourly traffic volume (in thousands per hour)	2.916	2.101	0.03	14.988
Truck percentage (%)	6.215	1.922	2.8	10.7
Road characteristic
Number of entering ramps per lane per mile	0.252	0.215	0	0.926
Number of lanes	4.159	0.562	3	5
Curvature (degree)	0.947	0.681	0	2.260
length of segment (miles)	1.014	0.769	0.236	4.5
Long remaining service life of rutting (1 if the value of rut is higher than 99, 0 otherwise)	0.225	na	0	1
Inside shoulder width (in feet)	9.006	2.583	5	15
Environmental and road surface characteristic
Cross wind speed	4.146	3.906	0	31.98
Visibility	1.075	0.136	0	1.1
Wet road surface	0.082	na	0	1
Chemical wet road surface	0.037	na	0	1