Fault-tolerant vehicle communications

A method in a vehicle equipped with a long-range interface and a short-range interface, the method comprising:

• maintaining a connection to an access network using the long-range interface;
• recording a time and a location at which the connection to the access network is operable;
• in response to failure of the connection to the access network, attempting to form a vehicle ad-hoc network (VANET) using the short-range interface;
• and
• sharing over the VANET, with other members of the VANET, the recorded time and location, or coverage information derived from the recorded time and location,
• wherein the method further comprises, in response to failure of the connection to the access network, at least one of the following steps:
• (i) from at least one other member of the VANET, receiving a time and a location at which the at least one other member's connection to the access network was operable;
• and from the recorded time and location and the received time and location, deriving coverage information indicative of a geographical boundary of an operable portion of the access network;
• and
• (ii) transmitting a connectivity query to other members of the VANET, and determining, on the basis of replies to the connectivity query, whether the connection failure is local or general.