Shun-Hui Chang , Chih-Yung Lin , Chun-Chia Hsu , Chin-Ping Fung , Jiun-Ren Hwang 報告者：楊子群

1. Shun-Hui Chang , Chih-Yung Lin , Chun-Chia Hsu , Chin-Ping Fung , Jiun-Ren Hwang 報告者：楊子群 The effect of a collision warning system on the driving performance of young drivers at intersections

2. Participants Investigated the driving performance of young drivers at intersections while driving a vehicle that was equipped with differentICWSs. (A driving simulator was employed in order to simulate an intersection accident that resulted from a violator’s vehicle running a red light. )

3. Participants

4. Participants

5. Participants 30 male subjects. Age : 20~25 years. (Average age : 23.1 years) Driver’s license at least 2 years. Average number of driving days per week was around two.

6. Apparatus Driving simulator : Six-degree-of-freedom Stewart motion platform. Virtual-reality-based visual and audio system. Vehicle motion simulation software. Computer Scene is updated at rates between 25 and 35 Hz.

7. Experimentaldesign Host vehicle was equipped with a collision avoidance warning system. Three conditions of the warning system : 　－beeping “bi-bi” 2khz and 70 db. 　－speech message “watch your left-hand(right-hand) side” 　－null signal Violation at a Seed of 70 km/h at a blind intersection from the left or right direction. Host vehicle at a seed of 50 km/h.

8. Experimentaldesign Two way, two-lane road, with 3.5-m-wide lanes and 1-m-wide pedestrian sidewalks. accelerating section (300 m) experimental section(5100 m) /located every 400–600 m in the experimental section/ braking section (900 m) 10–15 vehiclesincluding automobiles, motorcycles and pick-up trucks. The field of view for the drivers was about 56。 at thespecified position.

9. Procedure [ Step1 ] Subjects were asked to provide personal information. (gender, age and driving experience) [ Step2 ] Experimental instructions. [ Step3 ] Experimental practice.(20-25 min) [ Step4 ] Formal experiment.(7-10 min)

10. Data collection and statistical analysis reaction time Speed lateral position deviation accident rates All data were collected at 30 Hz. driving performance => Multivariate analysis of variance (MANOVA) different ICWS content. direction of the violator’s vehicle. location of intersection accident. number of driving days per week. post-hoc testing =>Tukey’s honesty significant difference (HSD). Accident rate=>chi-square test and path analysis.

11. Driving performance – Reaction time(1/2) A statistical difference was the threekinds of warning systems (F = 6.394, df = 2, p = 0.003) for the reaction time. Tukey’s HSD: The average reaction time at the first intersection was significantly longer than the time atthe non-first intersection(F = 5.765, df = 1, p = 0.019).

12. Driving performance – Reaction time(2/2) average reaction time taken by drivers who drove more than 1 day per week and drove less than 1 day per week was not statistically significant(F = 0.238, df = 1, p = 0.628). There were no interaction(交互)between any two traffic factors of the ICWS audio signals, the locationsof intersection accidents and the number of driving days per week. Discussion-reactiontime Suggested pay more attention when they enter an intersection than when they drive on a straight roadway.

13. Driving performance – Seed(1/3) Mean seed Mean speed did not reach statistical significance among the three ICWS conditions (F = 1.95, df = 2,p = 0.151). mean speed at the first intersection was significantly higher than the speed atthe non- first intersection (F = 7.36, df = 1, p = 0.009). The number of driving days per week did not have a significanteffect on the mean speed.

14. Driving performance – Seed(2/3) Standard deviation of speed Standard deviation of speed among the threeICWS conditions reached statistical significance (F = 3.44, df = 2, p = 0.038). The standard deviation of speed between the first and non-first intersection was not statistically significant difference. The number of driving days per week did not have a significant effect on the standard deviation of speed.

15. Driving performance – Seed(3/3) Discussion-seed A high driving speed may require a longer brake time in order to avoidan accident. When drivers were not awareof any violator vehicles at an intersection and maintained a high driving speed, their reaction time was long.

16. Driving performance – Lateral position deviation There were no significant differences in the lateral control over the host vehicleamong the three ICWS conditions.

17. Driving performance – Accident rate(1/4) Accident rate = The number of violator intersections in which the ICWS system did not generate a signal Number of accidents Beep warning : 16% Speech warning message : 26% no signal : 44% Statistically significant (χ2 = 8.294,p = 0.016) among the different ICWS conditions: With regard to the violator’s direction(方向), the violator vehicle was not statistically significant.

18. Driving performance – Accident rate(2/4) First intersection and non-first intersection was statistically significant(χ2 = 13.12, p = 0.000). Participantsdriving experience was statistically significant difference (χ2 = 4.35, p = 0.037).

19. Driving performance – Accident rate(3/4) Path Analysis: violator’s direction and lateral position deviation were not significant to the intersection accidents.

20. Driving performance – Accident rate(4/4) Discussion-accident rate If the driver noticed in advance that the violator, the reaction time would be reduced, and the subject would have more time to manage the traffic event.(Accident rate was reduced from 44% to 26% or 16%) Young and less-experienced drivers are in a high risk category. In this study, there was a higher accident risk at the first intersection. There was a higher accident risk at the first intersection.

21. Limitations 駕駛模擬無法模擬出如真實環境的複雜度，例如: 嚴重車禍(車輛翻轉)、車輛撞到時的感受等。