Comparing Handheld and Hands-free Cell Phone Usage Behaviors While Driving

<b>Objective:</b> The goal of this study was to compare cell phone usage behaviors while driving across 3 types of cell phones: handheld (HH) cell phones, portable hands-free (PHF) cell phones, and integrated hands-free (IHF) cell phones. Naturalistic driving data were used to observe HH, PHF, and IHF usage behaviors in participants’ own vehicles without any instructions or manipulations by researchers.<b>Methods:</b> In addition to naturalistic driving data, drivers provided their personal cell phone call records. Calls during driving were sampled and observed in naturalistically collected video. Calls were reviewed to identify cell phone type used for, and duration of, cell phone subtasks, non–cell phone secondary tasks, and other use behaviors. Drivers in the study self-identified as HH, PHF, or IHF users if they reported using that cell phone type at least 50% of the time. However, each sampled call was classified as HH, PHF, or IHF if the talking/listening subtask was conducted using that cell phone type, without considering the driver's self-reported group.<b>Results:</b> Drivers with PHF or IHF systems also used HH cell phones (IHF group used HH cell phone in 53.2% of the interactions, PHF group used HH cell phone for 55.5% of interactions). Talking/listening on a PHF phone or an IHF phone was significantly longer than talking/listening on an HH phone (<i>P</i> <b>Conclusions:</b> Hands-free cell phone technologies reduce the duration of cell phone visual–manual tasks compared to handheld cell phones. However, drivers with hands-free cell phone technologies available to them still choose to use handheld cell phones to converse or complete cell phone visual–manual tasks for a noteworthy portion of interactions.