Navigation systems and green-driving advisory systems are now a common feature in modern vehicles. The interaction of drivers with such systems when driving must be considered to minimise distraction whilst maintaining the benefits provided. This research investigates the glance behaviours of drivers, assessed from video data, when using a navigation device (study 1) and a green-driving advisory device (study 2). The main research question addressed was ‘Does the device cause visual distraction that might be detrimental to safety?’ The main focus was to establish the number of glances of 2 s or more to the systems and relate this to driver safety (as stipulated in new guidelines for use of in-vehicle systems proposed by the National Highway Traffic Safety Administration (NHTSA) in the US).
Study 1 tested a Blom Ndrive G800 navigation device whilst study 2 tested the Foot-LITE device; a Smart’ driving system which incorporates Green Driving Support (GDS). In study 1, the subjects were specifically requested to drive a prescribed route of approximately 25 km and were directed by an experimenter who was present in the front passenger seat (baseline condition phase). After approximately 8 months, the same 10 subjects were requested to perform the same drive but using the navigation device to guide them around the route (experimental condition phase). In study 2, all subjects were asked to drive a prescribed route first without using the Foot-LITE device (baseline condition phase) and then some days later, with the Foot-LITE device (experimental condition phase).
In study 1, the percentage of eyes off road time for drivers was much greater in the experimental (with device) condition compared to the baseline condition (14.3 % compared to 6.7 %) but whilst glances to the navigation device account for the majority of the increase, there are very few which exceed 2 s. Drivers in study 2 spent on average 4.3 % of their time looking at the system, at an average of 0.43 s per glance; no glances exceeded 2 s.
In study 1, whilst glances to the personal navigation device account for the majority of the increase in eyes off road time (in accordance with intuitive expectations), when the durations of the glances are analysed, there were very few which are 2 s or more in duration. The average glance was 0.76 s which compared with average duration of glances to other target areas of 0.6 s, well below the proposed NHTSA guidelines. In study 2, the main outcome was that the total number of glances made was similar for each condition, at approximately 1100. Therefore glances to the in-vehicle Smart driving system during the experimental condition must have been reallocated from a different location. Around 75 % of the glances were between 0.2 and 0.6 s – also well below the NHTSA proposed guidelines. The results of the study have important design implications for future in-vehicle information systems.