1. Towards an express-diagnostics for level of processing and hazard perception Boris M. Velichkovsky et al. Transportation Research Part F 5 (2002) 145-156 學生：董瑩蟬

2. Purpose This paper investigated the driver’s eye movement and fixation duration time when hazards event present. This paper used simulation method to collect experiment data.

3. Reference There were 50% accident refers to missing or delayed hazard perception. (Nagayama,1978) There were 57% accident because human error, and 2.4% occurred from mechanical fault. (Treat et al.,1977) Some studies showed that the visual information processing divided to two-level model. (Hoffman, 1999; Trevarthen, 1986; Velickovsky, 1982) The first was search for object, the second was fixation on a few object.

4. Reference Green (2000) identified hazard that was the second level. The first step investigated eye movements that recorded distribution of fixation time. (Moray,1993) The fixation time was between 90 to 140 ms that saccades were more than 4°. And between 140 to 200 may be the object easy seen and continuously attended. (Pannasch et al.,2001)

5. Reference The previously study result showed fig 1.

6. Method Subject –12 male, age range between 24 to 36 years –They require to have driving licence –Driving experience more than 70000 km Equipment –SIRCA’ driving simulator –ARTEC eye tracking system –Video beamer with SXGA-resolution (JVCDLAG11) –1.5 × 2 m screen –Eye Link head-mounted system was record eye movements data

7. Method Process –The subject required to stand in front of screen with 3.5 m. –And the driving speed less than 50 km/h. –There was an training test (ca 20 min) before experiment. –The experiment session ca 40 min. –There was five times session on each of five consecutive weeks.

8. Method The eye track measured after 10 min of drive. At the experiment phase, subject must to respond the hazards event on the road. That average 50 s were occurred. And the really occurred 40%. The hazards event occurred at 25 m from subject.

9. Method Fig 2 showed that hazards event. Fig. 2. Sample screenshots taken from the experiment: (A) a potential hazard: a pedestrian facing the street and (B) an immediate hazard: the red traffic light at a crossing.

10. Result-Saccade amplitude and fixation duration The fixation duration between 90 to 300 that has large saccadic amplitudes. Fig. 3. (A) The frequency distribution of fixations (131 654 counts) from the experiment and (B) distributions of preceding and following saccade amplitudes across the range of fixation durations.

11. Result-Immediate hazards The fixation duration significant increased when hazard was presence. (F(1,11)=9.841, P<0.001). The fixation duration increased not change the over time. (F(4,11)=0.099,P>0.98) Fig. 4. Mean duration time for fixations around the appearance of an immediate hazard (overall 375 counts; ‘‘0’’ corresponds to the fixation at the moment of the critical event), separately for five consecutive drive trials. Fig. 5. Frequencies of fixation durations of three categories around the time of appearance of an immediate hazard (‘‘0’’ corresponds to the fixation at the moment of the critical event).

12. Result-Potential and immediate hazards versus base-line

13. The fixation duration was significant increase when potential hazards present at 25 m distance form the driver. (F(1,11)=7.914, P<0.001) The sudden increase in fixation duration was no significant different between potential hazard and immediate hazard. (F(1,11)=1.166, P>0.28) The fixations duration,after the potential hazards and immediate hazards, that has significant different. (F(1,11)=6.749, P<0.017) There was 81% immediate hazards that were already perception.

14. Result-Braking for red versus passing through

15. There were 12 cases that the subjects stopped for red. The successful breaking cases that fixation duration significant increase when red light was viewed foveal and parafoveal. (F(1,11)=12.779, P<0.001; F(1,11)=3.336, P<0.002)

16. Discussion Chapman et al. (1998) found that the fixation duration increased more than 100 ms when hazardous event was presence. And they showed that the eye movement was important information that led us to understand the drive task.

17. conclusion When hazardous event was presence that the fixation duration was significant increase. The fixation duration between 90 to 300 have more than 4° saccadic amplitude. The successful breaking cases that fixation duration significant increase when red light was viewed foveal and parafoveal.