Thanks for the contribution! We're going to pass on this one: km/h, m/s, and ft/s are the standard unit symbols (the slash is part of the notation — mph is just the customary exception), so removing the slashes would make the API nonstandard (ms in particular reads as milliseconds) and would break every existing caller. It also leaves the test suite failing, since ConversionsTest::testSpeedConversion calls convertSpeed() with the slashed units. If you'd like to contribute further, fixing the imprecise ft/s factor (1.097 vs the exact 1.09728) with an updated test would be a genuinely useful follow-up.