A
high-occupancy toll lane (or
HOT lane) is a type of
traffic lane or
roadway that is available to
high-occupancy vehicles and other exempt vehicles without charge; other vehicles being required to pay a
variable fee that is adjusted in response to demand. Unlike
toll roads, drivers have an option to use general purpose lanes, on which a fee is not charged.
Express toll lanes, which are less common, operate along similar lines, but do not exempt high-occupancy vehicles.