| Driving is an activity that mainly relies on drivers’ real-time inspection of environment information,process of the input information and decisions made out as a result,and the rational distribution of drivers’ visual attention is the guarantee for drivers’ safety.Therefore,visual distraction is a threat to drivers’ safety.The interaction between drivers and the In-vehicle Information System should be ranked as the main way leading drivers to visual distraction status.In this paper,a secondary task that imitates the In-vehicle Information System is designed,which will induce drivers to visual distraction status when they drive.The secondary task is subdivied into three levels according to the task’s complexity.Judging by the statistic,drivers’ eyes-off-road time goes up with the level of the secondary task.A city scenario and a highway scenario are built into the Driving Simulator of Tsinghua University.Correspondingly,the required traffic flows companying with the secondary task and rear-end hazard stimulations are programmed into the Driving Simulator.Both the driving data from the Driving Simulator and eye movement information from an eye tracker of in total thirty qualified drivers are collected.In this paper,influence from visual distraction and velocity on drivers’ lateral control behaviors and longitudinal control behaviors to own car,as well as their eye movement behaviors are analyzed in car-following situation.Thus,the effect from visual distraction on drivers’ car-following strategies and information attainment pattern can be investigated.It is found that,whatever drivers’ velocity,visual distraction will impair drivers lateral control ability to own car.However,regarding the longitudinal control behaviors to own car,drivers may seek some compensatory strategies,like lowering acceleration fluctuation and enlarging car-following distance,to lower down the accident risk.Additionally,the density and amount of information increase within visually distracted drivers’ vision,resulting in a change in drivers’ information searching pattern and diminishing visual attention to areas concerned with traffic environment.Rear-end stimulations are included in this paper.The influence from visual distraction,time headway and velocity on drivers’ reaction process and collision avoidance behaviors are analyzed.The investigation of effect from visual distraction on rear-end accident forming mechanism can provide support for researches on accident causation theory.It is found that,whatever drivers’ velocity,when drivers brake to avoid the collisions,drivers’ Perception Time and Reaction Time go up along with the increase of drivers’ visual distraction level,while drivers’ Response Time and Time to Collision(TTC)go down.It is assumed that visually distracted drivers’ reaction delay is mainly due to the delay of hazard information perception.Moreover,drivers’ braking process is also influenced by time headway.Drivers’ Response Time,Reaction Time and TTC decrease as the time headway declines.By statistic analysis,drivers’ average Rection Time of steering is higher than that of braking.Based on the analysis of drivers’ Reaction Time and TTC,several variables including drivers’ eyes-off-road time are put into the Support Vector Machine(SVM)Model to build multivariate nonlinear regression models of Reaction Time and TTC respectively.The Regression Squared Correlation Coefficient(RSCC)of Reaction Time model is 67.95% and the Mean Square Error(MSE)is about 0.33,indicating a reliable regression result of drivers’ Reaction Time.The RSCC of TTC model is 55.08% and the MSE is about 1.40,showing a just so-so regression result of TTC.The regression of Reaction Time and TTC can be of great help for the improvement of accident reconstruction technology and development of related driver assistant systems. |
