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

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

Participants Goal ReferencesMethodResults & Discussion researchercontent NPA (2007)In the Taiwan => 39% of intersections. Elvik & Vaa (2004)In the Norway => 40% of intersections. FHWA (2007) In the United States => 1)21% of fatalities occurred at intersections 2)40–45% of intersection or intersection-related crashes. Retting, Williams, Preusser, and Weinstein (1995) 22% of urban accidents result from drivers failing to halt at traffic controls. FHWA (2005)In United States => Crashes that were caused by running a red light resulted in an estimated 805 (8.75%) fatalities 交通部 (2007) In Taiwan => running a red light has been one of the top five causes of traffic accidents in recent years Lawrence (2003); Maycock, Lockwood, & Lester (1991); Monarrez-Espino, Hasselberg, & Laflamme (2006); Vernick et al. (1999); Waller, Elliott, Shope, Raghunathan, & Little (2001); Yokota, Haga, Ogawa, & Kokubun (2003) Age and experience of young drivers affect their driving behaviors, which correspondingly bring about a higher risk in driving.

Participants Goal ReferencesMethodResults & Discussion researchercontent Triggs & Smith (1996) Young driver more high accidents rate than other group. Engstrom, Gregersen, Hernetkoski, Keskinen, & Nyberg (2003) Evans (1991) BCC (2008) NSW (2008) MOT (2008) DOH (2007) Male more high accidents rate than female. BCAA (2008) Kweon & Kockelman (2003) Santokh (2003)

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. Goal ReferencesMethodResults & Discussion

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. Goal ReferencesMethodResults & Discussion

Experimental design  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. Goal ReferencesMethodResults & Discussion

Experimental design  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 vehicles including automobiles, motorcycles and pick-up trucks.  The field of view for the drivers was about 56 。 at the specified position. Goal ReferencesMethodResults & Discussion

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) Goal ReferencesMethodResults & Discussion

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. Goal ReferencesMethodResults & Discussion

Driving performance – Reaction time(1/2)  A statistical difference was the three kinds of warning systems (F = 6.394, df = 2, p = ) for the reaction time. Tukey’s HSD:  The average reaction time at the first intersection was significantly longer than the time at the non-first intersection (F = 5.765, df = 1, p = 0.019). typemeanPost hoc Beep1.38A Speech message1.45 A B Null signal1.73 B typemeanPost hoc Non-first intersection1.34A First intersection2.03 B Goal ReferencesMethodResults & Discussion

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 locations of intersection accidents and the number of driving days per week. Discussion-reaction time  Suggested pay more attention when they enter an intersection than when they drive on a straight roadway. Goal ReferencesMethodResults & Discussion

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 at the non- first intersection (F = 7.36, df = 1, p = 0.009).  The number of driving days per week did not have a significant effect on the mean speed. Goal ReferencesMethodResults & Discussion

Driving performance – Seed(2/3) Standard deviation of speed  Standard deviation of speed among the three ICWS 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. Goal ReferencesMethodResults & Discussion

Driving performance – Seed(3/3) Discussion-seed 1)A high driving speed may require a longer brake time in order to avoid an accident. 2)When drivers were not aware of any violator vehicles at an intersection and maintained a high driving speed, their reaction time was long. Goal ReferencesMethodResults & Discussion

Driving performance – Lateral position deviation There were no significant differences in the lateral control over the host vehicle among the three ICWS conditions. Goal ReferencesMethodResults & Discussion

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 ( χ 2 = 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. Type%Post hoc Beep warning16A Speech message26 A Null signal44 B Goal ReferencesMethodResults & Discussion

Driving performance – Accident rate(2/4) First intersection and non-first intersection was statistically significant ( χ 2 = 13.12, p = 0.000). Participants driving experience was statistically significant difference (χ 2 = 4.35, p = 0.037). Type%Post hoc Non-first intersection19A First intersection53 B Type%Post hoc More than 1 day per week24A Less than 1 day per week47 B Goal ReferencesMethodResults & Discussion

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

Driving performance – Accident rate(4/4) Discussion-accident rate 1)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%) 2)Young and less-experienced drivers are in a high risk category. 3)In this study, there was a higher accident risk at the first intersection. 4)There was a higher accident risk at the first intersection. Goal ReferencesMethodResults & Discussion

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。 Goal ReferencesMethodResults & Discussion