Modeling of Lateral Stability of Tractor-Semitrailer on Combined Alignments of Freeway

Table 6

Variance analysis of factors influencing on curved downgrades.

Source	Sum of squares	Df	Mean square	value	Critical value
Corrected model	0.325	9	0.036	21.211
Intercept	1.951	1	1.951	1146.316
Radius	0.208	3	0.069	40.808
Grade	0.035	3	0.012	6.873
Speed	0.081	3	0.027	15.953
Error	0.010	6	0.002
Total	2.286	16
Correct total	0.335	15