The Effect of Touchscreen Layout Division on the Usability and Driving Safety of In-Vehicle Information Systems

Compared to traditional physical controls, in-vehicle touchscreen interaction relies more on vision. Irrational In-Vehicle Information System (IVIS) interface layout design can lead to decreased driver performance and even serious traffic accidents. This study investigated the impact of IVIS layouts on usability and driving safety. We extracted and analyzed the current mainstream IVIS homepage layouts in the market and summarized four different layout structures. An experiment was conducted on a driving simulator to examine the usability of the IVIS layout design based on task reaction time, error rate, NASA-TLX (a subjective workload assessment scale developed by NASA), and subjective preference (PREF). The safety issues of IVIS layout design were also examined based on standard deviation lane position (SDLP), speed variation (SV), mean glance time, mean number of glances, and blink frequency. This study recorded and evaluated the driving performance of 40 participants during real driving tasks at four speeds (0, 60, 90, and 120 km/h). Results showed that there were significant differences in task reaction time, NASA-TLX, PREF, mean glance time, SDLP, and SV among the four layouts. Furthermore, we observed that these four layouts had varying effects on usability and driving safety at four speeds. In the stationary state, the three-partition layouts were more efficient, while the two-partition layouts had more advantages during driving. Meanwhile, the horizontal dock bar layout interfaces have more advantages compared to the vertical dock bar interface. The study provides empirical evidence for optimizing the IVIS interface layout design for enhanced usability and driving safety.