33 CFR §161.11

1. (a)A VTS may issue measures or directions to enhance navigation and vessel safety and to protect the marine environment, such as, but not limited to:
   1. (1)Designating temporary reporting points and procedures;
   2. (2)Imposing vessel operating requirements; or
   3. (3)Establishing vessel traffic routing schemes.
2. (b)During conditions of vessel congestion, restricted visibility, adverse weather, or other hazardous circumstances, a VTS may control, supervise, or otherwise manage traffic, by specifying times of entry, movement, or departure to, from, or within a VTS area.