Constant TIME_REGRESSION_RELATIVE 

const TIME_REGRESSION_RELATIVE: f64 = 0.50;

How much slower a route may run, relative to its own baseline time, before time_regressed reports a regression – whichever is larger, this or TIME_REGRESSION_FLOOR_MS.

Measured rather than assumed: running this suite twice in a row on the same machine varies each case’s time by at most a few percent, even the slowest case (Licata to Catania, tens of seconds). Fifty percent stays comfortably above that margin, with room for a shared CI runner’s noisier hardware, while still catching an actual regression in this crate – a sevenfold slowdown, not a fifty-percent one.