47 CFR 95.1731: Permissible GMRS uses.

The operator of a GMRS station may use that station for two-way plain language voice communications with other GMRS stations and with FRS units concerning personal or business activities.

(a) Emergency communications. Any GMRS channel may be used for emergency communications or for traveler assistance. Operators of GMRS stations must, at all times and on all channels, give priority to emergency communications.

(b) One-way communications. The operator of a GMRS station may use that station to transmit one-way communications:

(1) To call for help or transmit other emergency communications;

(2) To provide warnings of hazardous road conditions to travelers; or,

(3) To make brief test transmissions.

(c) Travelers assistance. The operator of a GMRS station may transmit communications necessary to assist a traveler to reach a destination or to receive necessary services.

(d) Digital data. GMRS hand-held portable units may transmit digital data containing location information, or requesting location information from one or more other GMRS or FRS units, or containing a brief text message to another specific GMRS or FRS unit.