Oz research has revealed that odd work hours are likely to induce high-risk sleepy driving.
Dr Simon Smith, the Queensland University of Technology, monitored nurses and their alertness as they drove to and from work.
Smith, Research Fellow at the university's Centre for Accident Research and Road Safety, found long-haul truck drivers were not the only ones suffering fatigue.
"We're particularly concerned about fatigue in urban driving and shift workers are good example of that, where people are getting very sleepy.
"You don't need to drive for very long for sleepiness to have an impact on driving, and (sleepy shiftworkers) are certainly driving for more than 10 or 20 minutes in urban environments," he added.
Dr Smith is due to present the findings at the Australasian Sleep Association Conference.