Full-Factorial DOE — Vehicle Braking in Winter

Quantifying the effects of speed, surface type, and traction control on winter braking distance requires rigorous statistical design under field conditions.

Design and execute a full-factorial 2³ experiment to determine which factors significantly affect winter stopping distance.

Executed 16 randomized runs with 2 replicates. Diagnosed heteroscedastic residuals, evaluated Box-Cox transformation, and applied blocked-replicate ANOVA in Minitab. Conducted multivariate interaction-effect analysis.

Identified speed as the dominant factor (p = 0.0055, effect = 21.4 ft) with a significant Speed × Surface interaction (p = 0.0333). Found traction control had no significant effect (p = 0.324) — a counter-intuitive, data-backed finding challenging common safety assumptions.