An Improved Deep Learning Model for Traffic Crash Prediction

Table 1

Summary statistics of analyzed continuous variables.

Variable	Mean	Std. Dev.	Min.	Max.
Independent variable
The number of major injury crashes per year per roadway segment	0.04	0.32	0	3
The number of minor injury crashes per year per roadway segment	0.41	0.54	0	9
The number of no injury crashes per year per roadway segment	1.23	1.74	0	22
Traffic factors
The logarithm of AADT per lane	3.53	3.74	2.93	4.51
Truck traffic percentage	6.71	4.98	1	33
Posted speed limits	38.65	6.69	30	70
Geometric design features
Segment length (miles)	0.81	1.03	0.02	12.31
Degree of horizontal curvature	1.51	3.23	0	14.00
Median widths	1.12	2.02	0	12
Outside shoulder widths	3.06	1.88	3.52	8
Pavement factors
International roughness index	65.85	27.75	25.45	182.58
Rut depth (in.)	0.13	0.05	0.06	0.41