It’s not that the controversial restart provisions in the July 2013 hours of service rule were bad, they just didn’t provide a significant improvement over the previous (and now proven effective) weekly reset—so they’re officially off the books, according to information posted Thursday by the Federal Motor Carrier Safety Administration.

The good news: Agency research confirmed that the 34-hour restart provides drivers the opportunity for needed sleep time and sleep quality to recover from any acute or cumulative fatigue, and to reduce stress. The “most robust finding” from the Virginia Tech Transportation Institute study was evidence that drivers were in need of sleep when they undertook a restart, and when they slept during restart they slept much longer than when they were working. Specifically, drivers averaged approximately 6.5 hours of sleep per day during duty periods, and 8.6 hours of sleep during restart periods.

“This finding clearly shows the importance of off-duty time and that drivers need this extra time to recover from sleep debt that is accrued during the duty cycle,” FMCSA concludes in its Research Brief. “Similarly, perceived stress was higher during the duty cycle as compared to the restart period, again highlighting the importance of the restart period. Therefore, though differences in the manner by which the restart provisions were used may be negligible with respect to the outcome domains, drivers do benefit from a 34-hour restart period.”

Yet because of that “negligible” impact, FMCSA has restored “to full force and effect” the 34-hour restart rule as it stood prior to the revision. The requirement for two off-duty periods of 1 a.m. to 5 a.m. in the agency’s hours of service rules will not be enforced, nor will the once-per-week limit on use of the restart, the agency has posted.

The outcome of the study had become known before the results were made public when the DOT Office of the Inspector General posted a letter to Congress confirming the validity of the report and its conclusions, prompting praise from the trucking industry and sharp criticism from some highway safety groups, who contend the study was “set up for failure.”