Literally, to fail to catch the bus because you are late. Figuratively, to miss an opportunity or to be late in getting involved with something (to miss the boat).
寝坊してバスに乗り遅れたので、会社に遅刻した。
I overslept and missed the bus, so I was late for work.
スマホ投資の波に乗らず、結果的にバスに乗り遅れた人が多い。
Many people ended up missing the boat by not jumping on the smartphone investment wave.
会議に遅れてバスに乗り遅れたと思われないように早めに出発した。
I left early so that it wouldn't look like I missed the bus by being late for the meeting.