Attention allocation patterns in naturalistic driving.

The key to safe driving is the adequate distribution of the driver's attention to the forward area and to other non-forward focal points. However, thus far, current methods are not able to well quantify the entire process of a driver's attention allocation. Therefore, this study proposed a novel concept of renewal cycles for representing and analyzing driver attention allocation. Using the 100-car naturalistic glance data, this study found that 90.74% of drivers' attention allocations were 2-glance renewal cycles. The findings suggest that the sample drivers usually separated their lapses of attention from the forward direction into several sequences by directing their vision back to the forward direction after each visual shift away from it. In addition, although a markedly smaller number of cycles were more than 3-glances (2.09% renewal cycles), drivers were certainly less aware of the frontal area and at a higher risk of having an accident during such cycles. This finding might have striking implications for accident prevention. This area of study deserves further attention. Among the generated renewal cycles, lots of them repeated frequently, especially cycles related to invehicle distractions. To analyze the different characteristics among various attributes, distribution of the common renewal cycles under different conditions was examined. As expected, drivers displayed different renewal cycles under various road conditions and with various driver intentions. Although these sample drivers were not representative, the preliminary research results were promising and fruitful for potential applications, particularly educating novice drivers.