Driver inattention represents one of the leading contributory factors to road crashes. Extended eyes-off-road time indicates reduced visual monitoring of the driving environment, regardless of the task being performed. Delayed response related to reduced visual monitoring of the environment increases the probability of critical incidents occurring in road traffic. While using mobile phones while driving is widely restricted by law, various in-vehicle devices are being operated regularly by drivers, including those not essential for safe vehicle operation. Safe driving requires not only perception and reaction to events ahead but also continuous awareness of the situation behind the vehicle, especially before and during maneuvers, such as turning, overtaking, or lane changing. Off-forward glances, thus, do not necessarily need to be associated with distraction. The main objective of this study is to examine whether necessary off-forward glances (specifically those associated with analysis of the situation behind the vehicle) are comparable in duration to glances associated with in-vehicle activities (e.g., interaction with in-vehicle systems). The results could also contribute to the definition of the most hazardous distracting activities. The results obtained prove that evaluating the situation behind the vehicle does not require glance shifts longer than 2 s, even in a complex driving scenario. In contrast, distracting activities, such as interacting with a vehicle touchscreen and selected modern in-vehicle systems or driving with a navigation system without audio information, generally involve longer off-forward glances than those required for analyzing the situation behind the vehicle, often exceeding 1.2 s.
Bucsuházy et al. (Fri,) studied this question.