Audit Reports

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DOT Can Improve Processes for Evaluating the Impact of Time Zone Changes and Promoting Uniform Time Observance

Project ID: 

What We Looked At 
The Department of Transportation (DOT) is responsible for fostering and promoting uniform time observance—including Daylight Saving Time (DST)—as well as evaluating requests to change time zones. Since 2015, at least 45 States have proposed legislation either to change their observance of DST or to establish permanent standard time. Recent Federal interest, such as the March 2022 U.S. House of Representatives Committee on Energy and Commerce hearing on DST and the Sunshine Protection Act of 2021, highlights the importance of DST and time zone changes to impacted communities. Given the recent interest and potential impact of time zone changes on transportation, we initiated this audit with a limited scope to assess DOT’s processes for evaluating and responding to requests from States and localities for time zone changes and DST exemptions. 

What We Found 
While DOT is responsible for evaluating and processing time zone change petitions from States and localities, it does not have written guidance in place specifically addressing how the petitions should be evaluated and validated. Instead, if it were to receive a petition, the Department would process the petition according to the general rulemaking procedures and DOT Order already in place. However, it has been roughly 12 years since the Department last processed a petition and officials currently responsible for this area were not involved in the process the last time it took place. In addition, although DOT does not have the authority to grant exemptions from DST, it is responsible for fostering and promoting uniform time observance. Yet, it does not have processes for monitoring localities that are not observing DST or their assigned time zone and may not be aware of possible instances of non-uniform time observance. In addition, the Department does not provide sufficiently detailed information for the public to promptly and accurately identify non-compliant localities. 

Our Recommendations 
The Office of the Secretary of Transportation concurred with all five of our recommendations to improve DOT’s evaluation of time zone changes and promotion of uniform time observance and provided appropriate actions and completion dates. We consider these recommendations resolved but open, pending completion of planned actions.





Closed on 03.15.2023
No. 1 to OST

Evaluate the convenience of commerce questions to determine whether they reflect modern commerce-related impacts of time zone changes and, if necessary, update them.

No. 2 to OST

Develop and implement guidance for collecting and validating information on the impact of proposed time zone changes that constitutes the best and most relevant evidence.

No. 3 to OST

Conduct a study and provide a summary of findings to the public on whether non-uniform adoption and observance of time zones and DST is a problem nationwide.

Closed on 02.14.2023
No. 4 to OST

Review time zone and DST-related content on the following DOT websites to identify errors and make corrections.
DOT website “Daylight Saving Time.”
DOT website “Uniform Time.”
BTS website “History of Time Zones.”
BTS website “History of Daylight Savings Time.”

Closed on 05.09.2023
No. 5 to OST

Develop and implement a process for maintaining and, when boundaries in the regulations change, updating a publicly available map and GIS dataset showing precise time zone boundaries.