(a) A Tribe with jurisdiction over a cultural site or area entry road can close it. The Tribe can carry this out:

(1) During periods when the Tribe or Tribal members are involved in cultural activities; and

(2) In order to protect the health and safety of the Tribal members or the general public.

(b) Cultural site or area entry roads designated through an agreement with a public authority may only be closed according to the provisions of the agreement. See §170.115(c).