Table 5.

Interaction between pairs of factors causing fatalities.

A∩B	Q (A ∩ B)	Q (A + B)	Interaction Type
Primary cause ∩ Types of primary responsible party	0.178	0.135	Enhance, nonlinear
Primary cause ∩ Road section type	0.162	0.117	Enhance, nonlinear
Primary cause ∩ Road type	0.156	0.131	Enhance, nonlinear
Primary cause ∩ Road line style	0.147	0.117	Enhance, nonlinear
Primary cause ∩ Zones	0.136	0.105	Enhance, nonlinear
Primary cause ∩ Roadside protection	0.135	0.101	Enhance, nonlinear
Primary cause ∩ Time interval	0.135	0.101	Enhance, nonlinear
Primary cause ∩ Day of the week	0.129	0.096	Enhance, nonlinear
Primary cause ∩ Topography	0.115	0.110	Enhance, nonlinear
Primary cause ∩ Seasons	0.115	0.097	Enhance, nonlinear

A ∩ B means superposition of A and B; Q (A ∩ B) means the q value of A ∩ B; Q (A + B) means the q value of A plus the q value of B.