Based on a literature review, Lyznicki et al.  concluded that younger drivers are a high-risk group for fatigue-related crashes. They suggested that higher risk of younger driver is primarily due to chronic sleep debt accumulated through poor sleep habits related to the young person’s lifestyle. Within the general group of young drivers, teenagers may be even more susceptible to effects of sleep loss than young adults.
Several studies found that young drivers, and males in particular, were the most likely to be involved in fall-asleep crashes . For example, Åkerstedt & Kecklund  studied the factors associated with involvement in early-morning crashes (from midnight to 6 am), controlling for driving exposure. They reported that the highest risk for early-morning crashes was for younger drivers. Their crash risk at this time was at least five times higher than their risk when driving at other times. The high risk for younger drivers was greatest for young males.
The age factor may also play a role with professional drivers. In a simulator study, Otmani et al  found that young professional bus and coach drivers had more difficulty to drive in a low traffic condition and felt sleepier during low traffic driving in the late evening than middle-aged professional drivers.