Critical Factors Analysis of Severe Traffic Accidents Based on Bayesian Network in China

Table 3

Network node variable assignment standard for single-vehicle and multivehicle traffic accidents.

Variable classification	Variables	Symbol	Type of variable	Variables assignment	Single-vehicle	Multivehicle
					Frequency	Frequency
Accident feature (result variable)	Number of deaths	De	Category variable	1 = 10–19 death, 2 = 20–29 death, 3 = 30 death, and more
	Number of injuries	In	Category variable	1 = 10 injury and less, 2 = 10–29 injury, 3 = 30 injury, and more
Driver behavior	Overspeed or not	Os	Category variable	1 = yes and 2 = no	1.435
	Misoperation or not	Mo	Category variable	1 = yes and 2 = no	1.597
	Mislane use or not	Iu	Category variable	1 = yes and 2 = no		1.62
	Fatigue driving or not	Fd	Category variable	1 = yes and 2 = no		1.88
Vehicle	Vehicle types	Vt	Category variable	1 = commuter bus and 2 = others	0.418	0.
	Driving status	Tc	Category variable	1 = turning and 2 = others	1.516
	Vehicle driving status	Cl	Category variable	1 = cross line driving and 2 = others		1.58
	Vehicle safety status	Bb	Category variable	1 = poor braking and 2 = others		1.62
Road	Pavement alignment	Sr	Category variable	1 = straight segment and 2 = nonstraight segment	1.694	1.30
	Physical separation	Ps	Category variable	1 = nonseparation and 2 = separation	1.210	1.38
Environment	Accident occurring period	Dt	Category variable	1 = daytime and 2 = night	1.290	1.40
	Workday or not	Wd	Category variable	1 = yes and 2 = no		1.32
	Weather condition	Aw	Category variable	1 = bad weather and 2 = good weather	1.710	1.72
	Visibility	Lv	Category variable	1 = low visibility and 2 = good visibility	1.677	1.50