Per FMCSR 395.8(f)(1), your Record of Duty Status (Log Book) should be updated:

Per FMCSR 395.8(f)(1), your Record of Duty Status (Log Book) should be updated:

• A. At each change of duty status.
• B. The next business day.
• C. When the DOT Officer suggests it should be done.
• D. At the beginning and end of each day.

Answer: (A)

The main idea here is that your Log Book must reflect changes in your duty status as they happen. When you switch from driving to on‑duty not driving, or from on‑duty to off‑duty (including sleeper berth), you update the log with the exact time of that change. This keeps the Record of Duty Status accurate so your hours of service can be properly calculated and checked during inspections. Updating only the next business day would allow gaps and inaccuracies in your record, and waiting for a DOT officer to suggest changes isn’t how the requirement works—the log must be current regardless of inspections. Recording changes only at the beginning and end of the day misses the many transitions that can occur within a single shift, making it impossible to verify actual hours worked.

The main idea here is that your Log Book must reflect changes in your duty status as they happen. When you switch from driving to on‑duty not driving, or from on‑duty to off‑duty (including sleeper berth), you update the log with the exact time of that change. This keeps the Record of Duty Status accurate so your hours of service can be properly calculated and checked during inspections.

Updating only the next business day would allow gaps and inaccuracies in your record, and waiting for a DOT officer to suggest changes isn’t how the requirement works—the log must be current regardless of inspections. Recording changes only at the beginning and end of the day misses the many transitions that can occur within a single shift, making it impossible to verify actual hours worked.