Which safety ratings are accepted for carriers?

The correct answer is based on the understanding that safety ratings for carriers are typically assigned based on their compliance with regulations and the overall safety performance. In this framework, "Satisfactory," "Conditional," and "None" are commonly utilized terms.

"Satisfactory" indicates that a carrier adheres appropriately to safety regulations and is fit to operate. "Conditional" denotes that while the carrier may be able to operate, it has some issues that need to be addressed for full compliance. "None" suggests that the carrier has not received a safety rating due to lack of sufficient data or compliance history. This structure serves to inform shippers and the public of a carrier's safety record and helps maintain industry standards.

The other options do not align with the accepted terminology used in evaluating carriers' safety ratings within the regulatory framework. Therefore, focusing on the accepted terminology helps reinforce understanding of safety rating systems in the transportation industry.