A Crash Severity Prediction Method Based on Improved Neural Network and Factor Analysis

Table 1

Summary of the selected variables.

Category	Variables	Value definition
Nonroad	(1) Accident type, (2) month, and (3) weekday	Categorical, categorical, and categorical
	(4) Location type, (5) light, and (6) Driver sex	Categorical, categorical, and categorical
	(7) Driver age, (8) driver restrain, and (9) vehicle year	Continuous, categorical, and categorical
	(10) Vehicle type and (11) weather	Categorical and categorical
Road	(12) Road characteristics and (13) road surface	Categorical and categorical
	(14) Road functional class and (15) curve angle	Categorical and continuous
	(16) Curve direction and (17) gradient direction	Categorical and categorical
	(18) Gradient percentage and (19) curve radius	Continuous and continuous
	(20) Curve degree	Continuous