以存活分析評估防撞警示系統績效

Survival Analysis to Collision Warning System Performance Evaluation

趙士淵(Shih-Yuan Chao)

指導教授 ： 許添本

國立臺灣大學/工學院/土木工程學研究所/碩士(2019年)

https://doi.org/10.6342/NTU201803134

摘要

本研究以存活分析觀察駕駛行為在防撞警示系統運作下的變化，作為評估防撞警示系統績效的依據。存活分析為以時間資料為重要變數的分析方式，根據衝突樣本時間變數及其設限狀態建立生命表，繪製Kaplan-Meier存活曲線觀察其存活率變化，再以Cox等比例風險模式分析影響時間變數的相關變數。防撞警示系統係根據本向來車車速快慢決定鄰向路口是否給予閃燈警示，設置於花蓮東華大學校內涵星莊外環道T字路口及理工二館外環道T字路口。涵星莊外環道T字路口常見之衝突型態為左轉穿越型衝突及右轉匯入型衝突，理工二館外環道T字路口常見之衝突型態為交叉型衝突及左轉匯入型衝突。透過現地交通調查，無人機空拍錄影取得車流影像資料，於軌跡處理軟體上將軌跡轉換為位置及速率之時空資料。以「後侵占時間PET」作為左轉穿越型衝突及交叉型衝突之指標，「碰撞時間TTC」作為匯入型衝突之指標，將車流軌跡時空資料量化為衝突樣本。衝突樣本根據嚴重度等級訂定設限程度，左轉穿越型衝突無門檻值全為完整資料，交叉型衝突超過3秒為右設限資料，匯入型衝突2秒以上為右設限資料。
結果指出，左轉穿越型衝突之存活曲線無異，交叉型衝突、匯入型衝突皆顯示為兩條相異曲線，且根據存活時間增加，判定有警示為防撞警示系統有效。進一步建立Cox等比例風險模式分析與衝突相關之變數，左轉穿越衝突相關變數為後車速率，交叉型衝突相關變數為警示及後車是否轉向，右轉匯入型衝突相關變數為警示、車頭角度差、直行車先到、行人干擾，左轉匯入型衝突相關變數為警示、車頭角度差。

關鍵字

防撞警示 ； 後侵占時間 ； 碰撞時間 ； 存活分析 ； Cox等比例風險模式

並列摘要

The Thesis focus on using survival analysis to the performance evaluation of the collision warning system. Survival analysis is a method analyzing the time as a dependent variable. The collision warning is to warn that the adjacent lane is coming a vehicle. The systems are set on the T-junction near Dormitory III and the T-junction near Science and Engineering Building II, which the common conflict types of former junction are left-turned crossing conflict and right-turned merging conflict and of latter junction are right angle conflict and left-turned merging conflict. Fly a drone to collect the trajectories of the vehicles intersect in an intersection, and manipulate the softwore “Tracker” to transform them into time-space data. The thesis uses Post Encroachment Time (PET) for left-turned crossing conflict and right angle conflict and uses Time to Collision (TTC) for merging conflict.
Based on the result of Kaplan-Meier curve, the "Warning" curve is different from "No Warning" curve for right angle conflict and merging conflict. Then it uses Cox proportion hazard function for further discussion of the relating factors of the conflicts. The significant variables of left-turned crossing conflict are rear vehicle speed. Of right angle conflict are warning and if rear vehicle turns. The common significant variables of merging conflict are warning and the angle difference of two vehicles. In addition, other significant variables of right-turned merging conflict are if the straight car first arrived the intersection and the pedestrian interference.

並列關鍵字

Collision Warning System ； PET ； TTC ； Survival Analysis ； Cox Proportion Hazard Function

參考文獻

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