A common carrier is a business that transports people, goods, or services and offers its services to the general public under license or authority provided by a regulatory body. A common carrier holds itself out to provide service to the general public without discrimination for the "public convenience and necessity". A common carrier must further demonstrate to the regulator that it is "fit, willing and able" to provide those services for which it is granted authority. Common carriers typically transport persons or goods according to defined and published routes, time schedules and rate tables upon the approval of regulators. Public airlines, railroads, bus lines, cruise ships, motor carriers (i.e., trucking companies) and other freight companies generally operate as common carriers.
Although common carriers generally transport people or goods, in the United States the term may also refer to telecommunications providers and public utilities. In certain U.S. states, amusement parks that operate roller coasters and comparable rides have been found to be common carriers; a famous example is Disneyland.
Regulatory bodies may also grant carriers the authority to operate under contract with their customers instead of under common carrier authority, rates, schedules and rules. These regulated carriers, known as contract carriers, must demonstrate that they are "fit, willing and able" to provide service, according to standards enforced by the regulator. However, contract carriers are specifically not required to demonstrate that they will operate for the "public convenience and necessity." A contract carrier may be authorized to provide service over either fixed routes and schedules, i.e., as regular route carrier or on an ad hoc basis as an irregular route carrier.
It should be mentioned that the carrier refers only to the person (legal or physical) that enters into a contract of carriage with the shipper. The carrier does not necessarily have to own or even be in the possession of a means of transport. Unless otherwise agreed upon in the contract, the carrier may use whatever means of transport approved in its operating authority, as long as it is the most favourable from the cargo interests’ point of view. The carriers' duty is to get the goods to the agreed destination within the agreed time or within reasonable time.
The person that is physically transporting the goods on a means of transport is referred to as the "actual carrier". When a carrier subcontracts with another provider, such as an independent contractor or a third-party carrier, the common carrier is said to be providing "substituted service." The same person may hold both common carrier and contract carrier authority.
In contrast, private carriers are not licensed to offer a service to the public. Private carriers generally provide transport on an irregular or ad hoc basis for their owners.
A sea carrier may also, according to the Hague-Visby Rules, escape liability on other grounds than the above mentioned, e.g. a sea carrier is not liable for damages to the goods if the damage is the result of a fire onboard the ship or the result of a navigational error committed by the ships master or other crewmember.
Carriers typically incorporate further exceptions into a contract of carriage, often specifically claiming not to be a common carrier.
An important legal requirement for common carrier as public provider is that it cannot discriminate, that is refuse the service unless there is some compelling reason (e.g. post doesn't allow to send cash). As of 2007, the status of Internet Service providers as common carriers and their rights and responsibilities is widely debated (network neutrality).
It is also important to remember that the term common carrier does not exist in continental Europe but is distinctive to common law systems, particularly law systems in the U.S.A.