Kenji Hagita

Eye-Gaze Tracking Analysis of Driver Behavior While Interacting With Navigation Systems in an Urban Area

With the advent of global positioning system technology, smart phones are used as portable navigation systems. Guidelines that ensure driving safety while using conventional on-board navigation systems have already been published but do not extend to portable navigation systems; therefore, this study focused on the analysis of the eye-gaze tracking of drivers interacting with portable navigation systems in an urban area. Combinations of different display sizes and positions of portable navigation systems were adopted by 20 participants in a driving simulator experiment. An expectation maximum algorithm was proposed to classify the measured eye-gaze points; furthermore, three measures of glance frequency, glance time, and total glance time as a percentage were calculated. The results indicated that the convenient display position with a small visual angle can provide a significantly shorter glance time but a significantly higher glance frequency; however, the small-size display will bring on significantly longer glance time that may result in the increasing of visual distraction for drivers. The small-size portable display received significantly lower scores for subjective evaluation of acceptability and fatigue; moreover, the small-size portable display on the conventional built-in position received significantly lower subjective evaluation scores than that of the big-size one on the upper side of the dashboard. In addition, it indicated an increased risk of rear-end collision that the proportion of time that the time-to-collision was less than 1 s was significantly shorter for the portable navigation than that of traditional on-board one.

Gaze measurement to evaluate safety in using vehicle navigation systems

It becomes popular to use smart phones as a car navigation system. Conventional navigation systems were already designed following the published guidelines to ensure driving safety; however, guidelines for the smart phone navigation system are still undeveloped. To assess the safety of these devices, the car navigation systems are integrated into a driving simulator. The experiments are carried out by changing the size and the position of the display. Gazing points of the drivers are measured when they are driving on the driving simulator following the instruction of the car navigation systems as well as obtaining questionnaires. The results indicate the frequency of eye movement increases when the display is installed close to the drivers eye, while total time gazing the display does not change significantly in all the conditions.

Analysis of the NOx and PM emission of the diesel passenger car through Real-time On-board Measurement

In this paper, we measured the mass emission of NOx and PM at the same time, which exhausted from a diesel passenger vehicle. The car was equipped with on-board system, and amount of emission gas, speed, and acceleration were measured. Consequently, in the condition where the speed and acceleration of a car were high, exhaust amount of both NOx and PM increased. Furthermore, there were conditions of the run only with the high amount of Nox and conditions of the run only with the high amount of PM.