HOV lane
US /ˌeɪtʃ.oʊˈviː leɪn/
UK /ˌeɪtʃ.oʊˈviː leɪn/

1.
a lane on a highway reserved for vehicles carrying a specified minimum number of passengers, typically two or more, to encourage carpooling and reduce traffic congestion
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During rush hour, the HOV lane moves much faster than the regular lanes.
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You need at least two people in the car to use the HOV lane.