49 CFR §368.1

1. (a)A Mexico-domiciled motor carrier must apply to the FMCSA and receive a Certificate of Registration to provide interstate transportation in municipalities in the United States on the United States-Mexico international border or within the commercial zones of such municipalities as defined in 49 U.S.C. 13902(c)(4)(A).
2. (b)A certificate of registration permits only interstate transportation of property in municipalities in the United States on the United States-Mexico international border or within the commercial zones of such municipalities. A holder of a Certificate of Registration who operates a vehicle beyond this area is subject to applicable penalties and out-of-service orders.