In the United States, the highway patrol is the part of the police force within a particular state that is responsible for making sure that the roads are safe and for dealing with drivers who break the law.
The Florida Highway Patrol shut down the 20-mile stretch of the interstate.
...highway patrol officers.
highway patrol in British English
(ˈhaɪˌweɪ pəˈtrəʊl)
noun
US
a police patrol with the responsibility of regulating traffic
highway patrol in American English
a police organization limited to activity on property owned or leased by a state, which controls highway traffic, investigates accidents, etc.