47 CFR § 95.1731 - Permissible GMRS uses.
(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.
(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.
(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.