riding time; travel time aboard a vehicle
Refers to the duration spent riding a vehicle such as a bus, train, or taxi. Often used in schedules, travel planning, and fare calculations.
The riding time from Tokyo to Osaka is about two and a half hours.
Since the travel time is long, I plan to bring a book.
所要時間 is a general term for the time required for a journey or task, while 乗車時間 specifically refers to the time spent aboard a vehicle.
乗車券 is a ticket for boarding, whereas 乗車時間 is the duration of the ride itself.
Compound of 乗車 (じょうしゃ, 'boarding a vehicle') and 時間 (じかん, 'time').