If you assume that the Po--che could sustain average braking of 0.9g, which I would think it could, or better, then the distance to stop calculated from 252 ft per second (172 mph) is approx. 1103 feet, if my old physics is correct. This is well short of a half mile (2,640 ft), which seems to be the journo's guess, as Doug says.
BTW, my brother-in-law was caught speeding in one of his Model T's, and he asked for written proof, he was so proud.
Dalton