, Former U of M Researcher, Mechanical Engineering
The crash risk associated with cell phone use while driving is a contentious issue. In response, some states are imposing restrictions on the use of hand-held phones. However, there is ample evidence that there remains a risk for hands-free phones due to the mental distraction associated with cell phone conversations. Moreover, many states are introducing Advanced Traveler Information Systems (ATIS) that may be accessed with cell phones while driving. In these contexts, there is a need for relevant research to determine the risk of cell phone use. One method to determine this risk is to compare the driver impairment resulting from cell phone use with that resulting from other identified risks in the driving environment. This study compared driver performance while using a cell phone to conditions of operating common in-vehicle controls and alcohol intoxication. In addition, the study examined the combined effects of being distracted and being intoxicated given that there is a higher risk of a crash if the driver engages in a combination of risk factors. Participants drove simulated scenarios in the Virtual Environment for Surface Transportation Research (VESTR) at the HumanFIRST Program, University of Minnesota. During each scenario, participants were to drive normally along a rural route and were exposed to a variety of traffic scenarios, while carrying out a variety of tasks involving vehicle maneuvering, cell phone use and operation of in-vehicle controls. In addition, half of the participants were impaired by having their Blood Alcohol Content (BAC) raised to 0.08. Driver impairment was measured in terms of driving performance expressed in several parameters. The results suggest that drivers engaged in the cell phone conversations or completing in-vehicle tasks were more impaired than drivers that were not involved in any distraction task. The distraction with in-vehicle controls tended to produce the largest impairment. Furthermore, drivers completing the secondary tasks had impaired reaction time and identification of target audio tones. The results of this study remind us that the seemingly simple act of using the controls and displays in our dashboards can be a very real source of distraction. This study also demonstrates that the mental component of cell phone conversations does significantly impair driver performance. Laws that only restrict hand-held phones may not be sufficient to reduce crash risk. Furthermore ATIS that are accessible by cell phones should be designed to minimize the risk of interacting with these systems while driving. Finally, there are differences in how drivers were able to compensate for partaking in sanctioned (alcohol) and consensual (secondary task) risk; namely that drivers were not able to adequately compensate for conflicts between specific resources applied to the primary driving task.
- Project number: 2003040
- Start date: 11/2003
- Project status: Completed
- Research area: Transportation Safety and Traffic Flow