North Carolina RADAR State Practice Exam

Why was 55 mph chosen as the national maximum speed limit?

1. It was the safest average for highways

2. It is the Median Energy Efficiency Speed

3. It aligned with state regulations at the time

4. It was a compromise among states

The correct answer is: It is the Median Energy Efficiency Speed

The choice of 55 mph as the national maximum speed limit was primarily influenced by safety concerns and the desire to reduce accidents and conserve fuel. The correct answer highlights factors that align more closely with safety and regulatory frameworks rather than an arbitrary standard relating to energy efficiency. While the concept of Median Energy Efficiency Speed suggests that there may be an ideal speed for maximizing vehicle efficiency, the implementation of 55 mph was more about enhancing road safety and ensuring compliance across states. The speed limit was also a reaction to fuel conservation needs during the energy crises of the 1970s. Furthermore, this speed limit was indeed a compromise among various state regulations and considerations about traffic safety, which led to its acceptance as a unified standard across the nation. This standardization was essential for effective nationwide enforcement and to promote consistency for drivers traveling across state lines. Understanding the context of how the speed limit was established reveals its roots in safety and public policy rather than purely energy considerations. Thus, while B incorrectly attributes the choice primarily to energy efficiency, the reality is tied significantly to the collective compromise and safety prioritization across states.