noun
three people riding together; triple riding
Typically refers to three people on a bicycle or motorcycle, often in contexts where it is illegal or dangerous.
自転車の三人乗りは法律で禁止されている。
Triple riding on a bicycle is prohibited by law.
彼らは三人乗りでバイクに乗って事故に遭った。
They had an accident while riding three on a motorcycle.
Refers to two people riding together; more common and often legal, while 三人乗り usually implies an overloaded vehicle.
Compound of 三人 (three people) + 乗り (riding, from 乗る).