| The aging population is becoming an increasingly serious problem and is gradually becoming one of the world’s major challenges.This is also a fundamental national condition that will continue to persist in China throughout the 21st century.Walking is an important activity in the daily lives of the elderly and is also an important means of maintaining healthy aging.However,due to declining physical and cognitive abilities,the elderly are an extremely vulnerable group on the road and are highly susceptible to collisions with vehicles and other pedestrians during walking activities.Therefore,it is of great social significance to explore the impact of built environments on the walking activities and safety of the elderly.Accordingly,this thesis takes the Yuzhong District of Chongqing City as an example and establishes appropriate models to explore the mechanisms of built environments on the walking activities and traffic accidents of the elderly.The research mainly includes the following aspects:1.Analyzed the characteristics of walking activities and traffic accidents among elderly people in Yuzhong district.Based on questionnaire data,the characteristics of elderly people’s walking activities in Yuzhong district were analyzed from aspects such as age,gender,and activity purpose.The obtained data on elderly people’s traffic accidents were analyzed from several aspects including the subject of the accident,natural environment,and spatio-temporal distribution.The results showed that there was a significant local clustering effect of elderly people’s traffic accidents in Yuzhong district,and there were accident-prone areas centered around Jiefangbei,Shangqing Temple,and Daping.Based on the"5Ds"element indicators,a built environment indicator system required for this study was established.Using geometric and spatial statistical operations,the built environment elements in the study area were visualized and briefly described.The collected data provided a basis for subsequent analysis of elderly people’s walking activities and traffic accidents.2.Modeling and analysis of the impact of built environments on elderly walking activities.The study established a gradient boosting regression tree(GBRT)model that does not require assumptions or presetting and can more effectively handle multicollinearity.The GBRT model can model complex nonlinear data and capture the nonlinear effects of independent variables,thus obtaining more accurate and stable results.Using this model,the study examined the importance and nonlinear effects of built environment factors such as land use,proximity to facilities,road facilities,and social economy on elderly walking activities.Compared to the ordinary least squares model(OLS),random forest(RF),and extreme gradient boosting decision tree model(XGBoost),the GBRT model demonstrated stronger fitting performance,with an Adjust＿R~2of 0.457.In subsequent interpretive analysis using the GBRT model as the baseline,the results of the single variable impact effect showed that the cumulative importance of all built environment variables was 71.59%,much higher than that of individual characteristics variables(28.41%).Commercial service land use,land use mixing degree,residential land use,distance to vegetable markets,and building density had relatively high relative importance in built environment variables,and all variables exhibited significant nonlinear and threshold effects.3.Modeling and analysis of the impact of built environments on elderly walking safety.Based on research on the relationship between built environments and individual walking activities,combined with elderly traffic accident data in Yuzhong District,the study used traffic behavior theory and intermediate effect theory to incorporate elderly walking activities into the analysis of the impact of built environments on elderly traffic accidents,considering the mediating effect of elderly walking activities in the relationship between built environments and elderly traffic accidents.The study constructed a research framework of"built environment-walking activity-traffic accidents."The results showed that elderly walking activities exhibited significant mediating effects in the relationship between built environment factors and elderly traffic accidents.Finally,based on the above analysis,the following planning strategies are proposed to encourage elderly people to walk actively while reducing the likelihood of traffic accidents involving elderly pedestrians:(1)Reasonable layout of various facilities to promote safe walking for elderly people.(2)Improve pedestrian spaces and reduce obstacles for elderly people walking.(3)Enhance the safety of elderly people’s public transportation by improving bus stops. |
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