Naturalistic study on the usage of smartphone applications among Finnish drivers

•We tracked how Finnish drivers use their smartphones while driving.•The drivers produced more touches per hour on urban roads compared to other roads.•The instances of use tend to be shorter on urban roads compared to other roads.•The smartphone heavy-users did not reduce phone use based on traffic density.•The greatest risk from smartphone use may be caused by messaging applications. We present results from a naturalistic study that tracked how Finnish drivers use their smartphones while on the move. We monitored 30 heavy in-car smartphone users in Finland during June–September 2016, recording the times that they used their phones, the application used at the time of touch (calls excluded), the location and driving speed. Touches per time unit were used as a proxy for estimating visual-manual distraction due to visual-manual tasks. Our data set allows the determining of whether drivers use their phones differently on varying road types (highway, main road, local rural road, urban road). We found that the road type has an effect on phone use but the effect is contrary to what we expected. Drivers produced more touches per hour on urban roads, yet the use instances tend to be shorter than on the highway or main roads. We also collected statistics on the applications that were used. By far the highest overall rankings in the number of drivers using, number of uses, and duration per use instance was associated with the WhatsApp messaging service. One instance of WhatsApp use had a median of 8 touches, and had a median duration of 35 s. In contrast, navigation application use included a median of 3 touches and lasted for 11 s. The findings suggest that the Finnish smartphone heavy-users do not decrease their phone use when the demands of the traffic conditions increase and that the greatest risk from smartphone use may be currently caused by messaging applications.