Carpooling is shared use of a car, in particular for commuting to work, often by people who each have a car but travel together to save costs. There are sometimes special facilities for carpoolers, including high occupancy vehicle lanes specifically for cars with multiple riders.
Carpooling (also known as ride-sharing or, in the UK, lift-sharing and even, confusingly, as car sharing, is shared use of a car, in particular for commuting to work, often by people who each have a car but travel together to save costs.
Carpool projects have been around in fairly structured form going back to the mid-seventies, and in recent years have begun to make much more extensive use of the internet and software support systems.
Carpooling combines many of the disadvantages of public transportation (lack of privacy, not on-demand) with the disadvantages of the automobile (low safety, high fuel consumption, high cost of labour).