Regulated Navigation Areas (RNA) as outlined in 33 CFR Part 165 are established to regulate vessels and their movement within a specific area. The District Commander can issue an RNA to control vessel traffic in a place determined to have hazardous conditions. RNAs usually prescribe what type or size of vessels may enter an area or in what manner they must navigate. RNAs differ from Safety and Security Zones in two respects. First, only District Commanders are authorized to establish RNAs while Coast Guard Captains of the Port may not. Second, Safety and Security Zones are typically transitory in nature, responsive to a temporary safety or security concern on the water. They are meant to control access to an area, but they could also be used to control access based on compliance with specified temporary operating conditions within the Safety or Security Zone necessary for the purpose of the zones creation. RNAs are usually created where a more permanent solution to a safety or environmental concern is required. They principally regulate the operation of vessels permitted inside the area, but may also establish control of access to an area if necessary.