Analyzing The Dependence Of The Future Elderly On Private Cars And The Effects On Traffic Flow

As the ageing process develops on a global scale,the travel behaviors of the elderly are quietly changing.Studies of the western developed countries have showed that the elderly today become increasingly depending on pr ivate cars,as compared to a generation ago.However,as the number of the elderly drivers increases,road traffic safety situation becomes not optimistic and has attracted lots of attention from relevant government authorities as well as many researchers.China is at the early stage of rapid development of urbanization and motorization.The preferred mode of transport for the elderly is the walk,and they are less likely to use private cars to complete their daily trips.But as the motorization progresses,it can be foreseen that the travel behaviors of the future elderly in China will make great changes.Base on the further development of ageing and motorization processes,the aim of this study is to investigate the dependence of the future elderly on the private cars and corresponding influence factors.In addition,the effects of the elderly drivers on road traffic are also analyzed and quantified.This study investigated the dependence of the future elderly on the private cars.Based on the SP survey on the travel willingnesses of the young and middle-aged people when they are 65 years old,the car ownership of the future elderly and corresponding influencing factors were investigated by adopting an Ordered Logit model.In addition,the mode choice behaviors for the future elderly was also analyze by using the MNL model.And the results demonstrated that the future elderly have higher propensities to own private cars and to conduct their shopping trips by driving a car.In addition,the influencing factors,like gender,attitude and preference,have significant impacts on the mode choice behaviors for the future elderly.This study investigated the driving behaviors of the elderly drivers.The driving behaviors data of the elderly and young drivers on the urban expressways and main roads were collected by a driving simulator.The analysis of variances showed that the elderly and young drivers have significant difference in mean headway,standard deviation of headway,standard deviation of speed,total response time,braking-response time and so on.This study analyzed and quantified the effects of the elderly drivers on road traffic by adopting the computer simulation technique.Based on the car following data collected by the driving simulator,combining t he BP neural net algorithm and traffic flow theory,the car following models of the elderly and young drivers were established.The simulation results demonstrated that an increase in the number of the elderly drivers would lengthen the motorcade,widen the range in the variation scope of speed,and increase the time required to return to stable car following states.Furthermore,based on the driving behaviors of the elderly drivers,the two-lane traffic cellular automaton(CA)model was also constructed.After the simulation,it was found that the elderly's driving behaviors have great effects on road capacity,the stability of traffic flow,and the rate of traffic accidents.The findings in this study can provide valuable references for the aging society when making transport polices in China.The traffic flow simulation models considering driving behaviors of the elderly can be used for impact analysis of traffic measures which are designed to tackle the elderly's travel problems.