Distinguishing between Rural and Urban Road Segment Traffic Safety Based on Zero-Inflated Negative Binomial Regression Models

Table 1

ZINB models for segment crash frequency analyses and predictions.

Role	Variables	Types	Description
Dependent variable	Num_crsh	Continuous	Number of crashes (crash frequencies)
	ADT_1000	Continuous	Average thousand daily traffic (thousand vehicles per day)
	Length	Continuous	The length of a segment (mile)
	FFS	Continuous	Free flow speed in road segment (mph)
Independent variable	Daily_VMT	Continuous	Average daily Vehicle Mile Traveled (VMT)
	RorU	Discrete	Rural or urban: 0 = urban; 1 = rural
	FC	Discrete	Segment functional classification: 0 = interstate; 1 = expressway; 2 = arterial; 3 = M_Arterial
	Numberofla	Discrete	Number of lanes: 0 = 2 lanes; 1 = 4 lanes