Texting with a smartphone in a dashboard mount

In the Netherlands, handheld phone use while driving is prohibited. However, mobile phone use while driving is allowed when the phone is placed in a dashboard mount. Many studies have shown that handheld texting is a major concern for traffic safety because it negatively affects driving performance and increases crash rates. The objective of this study was to investigate driving performance during handsfree texting and to compare it to handheld texting while driving. Participants were seated in a driving simulator wherein they drove three times on the same dual carriageway while wearing a head mounted eye-tracker. While driving, participants texted once handheld, once handsfree and during one drive they did not text (baseline). During the handheld and handsfree texting drives they received three short test messages to which they had to reply. These questions were easy to understand and elicited one-word replies of approximately ten characters. Whenever a participant did not know how to reply, they were instructed to answer the Dutch equivalent of ‘I don’t know’ (‘weet ik niet’) or something of their preference. Participant’s gaze behavior was measured using a head-mounted eye-tracker, driving performance was measured by using the standard deviation of both the lateral position and speed and subjective workload was measured using the Rating Scale for Mental Effort (RSME). The results show that participants looked significantly more often at the phone in a dashboard mount compared to when they were texting handheld. Additionally, the total dwell time on the smartphone was also longer while texting handsfree compared to texting handheld. There were no significant differences between the texting drives on the number of glances longer than 2 seconds, longest glance and mean fixating duration at the smartphone. Compared to the baseline drive, the total dwell time in the mirrors was much shorted during the two texting drives. The standard deviation of the lateral position and the standard deviation of speed was lower during both texting drives. Lastly, the experienced subjective workload was higher during both texting drives compared to the baseline drive, and was highest during the handheld texting drive. These results indicate that handsfree texting is at least as unsafe and detrimental to the execution of the driving task as handheld texting.