Investigating the speech of the English upper class in 1956, the linguist Professor Ross identified U(pper) and Non-U(pper) features. ‘Pardon’ was a non-U term used
(1) when the hearer didn’t hear the speaker properly;
(2) as an apology (eg on brushing by someone in a passage); and
(3) after hiccuping or belching.
The U equivalents were (1) What? (2) Sorry (3) (Silence).
These days, I suspect AmEng uses Excuse me more often for (1) and (2) than does BrEng, which prefers Sorry. BrEng mainly uses Excuse me for (3) and perhaps AmEng does too.
If you bump into someone on a British street, the bumped is just as likely as the bumper to say Sorry.