A high-occupancy vehicle lane (also HOV lane, carpool lane, diamond lane, and transit lane) is a restricted traffic lane reserved at peak travel times or longer for exclusive use of vehicles with a driver and one or more passengers. The normal minimum occupancy level is 2 or 3 occupants. HOV lanes are normally created to increase higher average vehicle occupancy and person throughput with the goal of reducing traffic congestion and air pollution.

拼车专用道（carpool lane），也叫高上座率机动车道（high-occupancy vehicle lane，HOV lane）、钻石车道（diamond lane）或快速车道（transit lane），指在交通高峰时段专门预留给那些除司机外还搭乘有一名或多名乘客的机动车行驶的车道。每辆车最少要载有2到3个人。开设拼车专用道是为了提高车辆的平均上座率和人员通行量，以缓解交通拥堵和空气污染。