The study, recently published in Mayo Clinic Proceedings, found that residents attributed the traffic incidents to fatigue and to distress -- including feelings of burnout or depression.

"Just like any other field, residents need their recovery time. In order to make good decisions, physicians need to be physically and emotionally well," says lead author Colin West, M.D., Ph.D., an internal medicine physician at Mayo Clinic. "Residents need to be rested. We don't want them to have undue amounts of stress."

It is well documented that medical residents often work long and grueling hours during their three-year residencies. The intense work schedule has benefits, Dr. West says. For example, residencies prepare trainees to become independent physicians. However, it's important that educators continually update their approach to retain the value of the training while minimizing stress and fatigue, he says. In addition to the 11 percent who had traffic crashes, 43 percent reported narrowly avoiding them.

"The mere fact that motor vehicle incidents are common among residents brings the issues of resident fatigue, sleepiness and distress to a new level of priority," Dr. West says. "New interventions designed to address both resident fatigue and distress may be needed to promote patient and resident safety."

Residents also were asked about the frequency of self-reported blood and body fluid exposures. Of the about 300 residents in the study, 23 (about 8 percent) reported having at least one blood and body fluid exposure due to fatigue or stress during the study period.

To gather the data, participants completed surveys quarterly from July 1, 2007, through July 31, 2011, during their training period. Associations of validated measures of quality of life, burnout, symptoms of depression, fatigue and sleepiness with a subsequently reported blood and body fluid exposure or motor vehicle incident were determined from these survey results.

The study was funded by the Mayo Clinic Department of Medicine Program on Physician Wellbeing.