49 CFR § 673.21
General requirements
November 18, 2020
Each transit agency must establish and implement a Safety Management System under this part. A transit agency Safety Management System must be appropriately scaled to the size, scope and complexity of the transit agency and include the following elements:
(a) Safety Management Policy as described in §673.23;
(b) Safety Risk Management as described in §673.25;
(c) Safety Assurance as described in §673.27; and
(d) Safety Promotion as described in §673.29.