At 55 mph, on dry pavement, in ideal conditions, what is the minimum total stopping distance for a commercial motor vehicle according to the AAMVA CDL manual?

49 CFR 383.111(a)(9); AAMVA CDL Manual (nhcdm.pdf) Section 2.6.1, pp. 2-13 to 2-14, Figure 2.11

Total stopping distance at highway speed is longer than most drivers expect, nearly a football field and a half at 55 mph, because it includes the time your brain needs to notice a hazard and your foot needs to reach the brake, not just the braking itself. Underestimating this is a direct cause of rear-end and following-too-close crashes with large vehicles, which take far longer to stop than cars.