The concept of ride sharing is not new, but there is great disparity between the way schemes have been developed in different countries. The disparity includes differences in terminology. Ride sharing can be loosely defined as any process which facilitates a car driver giving a lift to another person. This can range from informal lift giving between friends and family to a formally organised workplace scheme for journeys to and from work. Ride sharing (a European term) is variously known as lift giving, car pooling (in North America) and car sharing (in the UK). In the UK, a car pool is the term used to describe the situation where a company owns one or more vehicles for use by its employees on company business as and when needed.

Ride sharing differs from a car club in that the former requires drivers to possess their own vehicles. Where as members of a car club do not need to possess their own vehicles. Drivers become members of a club from which they can hire a vehicle for short periods. The passengers who participate in ride sharing can be other car owners or non-car owners.

There are many ways of managing demand for car travel. One group of measures that seek to do this are those designed to reduce the demand by facilitating new ways of travelling by car and/or providing alternatives. Ride sharing falls within this category.

Demand impacts may not always be in terms of a reduction in car use, and impacts can fluctuate over time as individuals' arrangements change.