Table 3. Symbols and definitions of variables in the ordered logit model.

Variable and Symbol	Definition	Frequency
Vehicle Type	x1 = 1, Small Vehicle	709
x1	x1 = 2, Large Vehicle	507
Rain Intensity	x2 = 1, Level of Rain Intensity = I	303
x2	x2 = 2, Level of Rain Intensity = II	303
	x2 = 3, Level of Rain Intensity = III	305
	x2 = 4, Level of Rain Intensity = IV	305
Location	(x3, x4) = (0, 0), Roadway	402
x3, x4	(x3, x4) = (1, 0), Toll Gate	407
	(x3, x4) = (0, 1), Ramp and Weaving Area	408
Traffic Volume	x5 = 1, Low Volume (Level of Traffic Volume = I, II)	606
x5	x5 = 2, High Volume (Level of Traffic Volume = III, IV)	610
Level of Impact	C = 1, Slight Impact	220
C	C = 2, General Impact	350
	C = 3, Serious Impact	375
	C = 4, Catastrophic Impact	271