Guettler limits computed using friction coefficients obtained from measurements. Conditions A and B are shown in (a), while conditions C, D, and D* are displayed in (b). Ten increasing values of $\widehat{a}$ were employed, ranging from 0.15 ms⁻² to 3.15 ms⁻², as indicated by the arrows. For comparison, dashed lines represent limits computed with a fixed set of friction coefficients (μ_s = 1, μ_d = 0.5, μ_d1 = 0.4, μ_d2 = 0.3) used in Figure 10.