• naturalistic driving

    A new approach among already applied traffic research methods

Driver distraction in commercial vehicle operations

Data from two previous naturalistic studies were summarized. Combined, the two data sets represented 203 commercial vehicle drivers, and approximately 5 million km of data including kinematics and video data. The dynamic performance measures included longitudinal and lateral acceleration and braking, the video included view of the driver’s face, as well as forward and backward (left and right) roads.

Trained data analysts identified so-called safety critical incidents defined as crash, near-crash, and crash-relevant conflicts. This was done by running the data through a software programme in which incidents were flagged based on certain thresholds: longitudinal acceleration (hard-braking), time-to-collision, swerve, critical incident box and analyst identified. For each safety-critical incidents, the analyst defined type of conflict, potential distractions, driver behaviour, and road and environmental conditions.

4452 safety-critical events were identified in the dataset, including 21 crashes. In order to be able to estimate odds ratios, baseline events were also gathered, i.e., uneventful, routine driving.

Defining distraction as tertiary tasks, i.e., not driving-relevant distractions such as texting, eating etc., a distraction factor was present in 60 percent of all safety-critical incidents.

The highest risk was associated with texting on cell phone, followed by other complex tasks (cleaning side mirror etc.), and interacting with or looking at dispatching device. Interestingly, talking or listening to a hand-held phone was not significantly associated with increased risk, whereas talking/listening to a hands-free phone was associated with decreased risk, i.e., had an protective effect.

The results clearly show that the tasks associated with the highest risk are those in which the drivers’ eyes are drawn away from the forward roadway.

Source: Olson,R.L., Hanowski,R.J., Hickman,J.S., Bocanegra,J. 2009. Driver distraction in commercial vehicle operations. Report FMCSA-RRR-09-042. Washington, DC: US Department of Transportation



Report on driver distraction

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Last update: November 20, 2009