also: ラッシュ・アワー
Refers to the peak traffic periods in the morning and evening when roads and trains are most crowded.
Trains are very crowded during the morning rush hour.
I commute avoiding rush hour.
I got caught up in rush-hour traffic because of an accident and was late for work.
I left home early to avoid rush hour.
It's about to become rush hour, so the station will start getting crowded.