Is the ability to operate a cell phone via Bluetooth influenced by the driver’s vehicle?

Martin Lavallière is a professor in the Department of Health Sciences (Kinesiology Program) at the University of Quebec in Chicoutimi. His research focuses on road safety, human factors and ergonomics and mobility and autonomy. This blog is the first in a series that will examine critical issues related to driver distraction and the effect of driver training on older adults and people with traumatic brain injury.

At the last Canadian Association of Road Safety Professionals (CARSP) conference, you presented on the task complexity of using cell phones linked to a vehicle via Bluetooth while driving. This was based on a study you conducted with colleagues from the MIT AgeLab & New England University Transportation Center. What was the motivation for this research? How do you think it relates to Vision Zero?

Unfortunately, the use of cell phones while driving has become increasingly more common. Original equipment manufacturers (OEMs) are racing against each other to integrate cell phone technology into vehicles, despite a growing body of research suggesting this is unsafe for driving. Recent data suggests that deaths caused by distracted driving are on the rise [1] and some researchers have suggested that the rapid proliferation of novel DVIs may be responsible for lapses in driver attention [2].

Our study aimed to better understand driver interactions with DVIs when making a call, using a hands-free mode, which is now the norm. We hope a better understanding of how these interactions impact driving performance will lead to safer human-machine interfaces (HMIs) that decrease the number of collisions involving distracted driving.

How is your study different from previous research? And what do you see as the benefit in working with the Parachute Vision Zero Network?

Through the use of hierarchical task analysis across a large number of vehicles, we found substantive differences in the number, and types of interactions employed. 

Studies on the impact of cell phone entry while driving are often based on surrogate tasks not exactly the same as phone entry or Wizard-of-Oz implementations (i.e. design by the research team and not commercially available).

As researchers, the benefits of collaborating with Parachute Vision Zero Network is it helps us to spread information related to driving safety, and in this case, how distractions will impact one’s abilities to drive safely.

What were the main findings of your study? What can we learn from all this?

The results of the task analysis found a good deal of variability across manufacturer, region, and the task difficulty, with the total number of operational steps for a driver ranging from a low of three to a high of nine. 

The most frequently encountered manual input used across the HMIs was the button press, and considered both physical and touch screen “buttons”. Five of the HMIs also employed a rotational controller (knob) to access the information, e.g. if a contact name is located down the list, the user may need multiple rotations to reach that particular contact. It cannot be assumed that two HMIs of the same general class (e.g., a visual-manual interface for selecting a contact from a phone list) are likely to place similar attentional or other demands on the driver. In addition, since not all rotating knobs respond the same way (i.e., the same rotational angle could move one line or several on a list, or even a whole “page”), thus this factor needs to be considered in an in-depth assessment as well.

Were there any limitations to this study? Please explain.

There are two limitations to this study. First, a well-trained experimenter placed the phone call with each vehicle’s interfaces. Since the experimenter knew the contact name and workflow architecture of the task well for each vehicles tested in this protocol, and what was required to complete the task without errors, it remains to be established how a lay-driver on the same system would perform. Second, the vehicles used in this study were parked, thus operation of these interfaces in the “real-world” (i.e., while driving) could result in a different process or number of steps for completing the task, completion time and glance behaviors, therefore caution should be taken in interpreting how these task analysis data translate to the context of driver safety during vehicle operation.

What do you see as the next steps in terms of future research? What do you hope will come out all of this? 

The use of “novice” users, those not extensively trained on an interface, could be considered for future studies to better understand how individual design implementations are used by individuals unfamiliar with the underlying design model. Evaluation across the lifespan could also be interesting to evaluate if certain types of interfaces are more effective (i.e. less errors and less gaze off-road) for different age groups.

Though the focus is this study was on the minimum number of operations required to complete a task, variations in the size and location of buttons, rotational controls, and screen components of the HMIs examined is also expected to impact the speed and other characteristics of these interactions. Future work will need to examine the timing of these interactions in addition to their frequency in order to better understand the impact of these systems on driver attention allocation and situational awareness.

1.NATIONAL CENTER FOR STATISTICS AND ANALYSIS, Early estimate of motor vehicle traffic fatalities for the first half (Jan-Jun) of 2016. 2016, National Highway Traffic Safety Administration.: Washington, DC.

2. REGAN, M.A., J.D. LEE, and K.L. YOUNG, Driver distraction theory, effects and mitigation. 2009, Boca Raton, FL: CRC Press, Taylor and Francis Group. 654.