Top: correlation between λ and ρ₂/ρ₁ for a) non-detected ICME shocks (f_ICME = − 1) and b) shocks associated with ICMEs (f_ICME = 0,1 and 2). The correlation is very weak for both cases. Middle: correlation between λ and the shock speed V_sn for c) non-detected ICME shocks and d) shocks associated with ICMEs. The correlation between the two parameters is very large, and the same tendency is found for different types of shocks. This tendency is compatible with V_sn∝ cosλ (green dashed lines). Bottom: e) correlation between λ and the ICME ΔV (difference between the front and the rear velocities), and f) correlation between λ and Dst for shocks with ICMEs.