應用資料探勘技術針對肇事碰撞型態建立路口分支風險和肇事因子模型

Accident type-based analysis of risk and collision factors using data mining techniques

蕭唯倫(Wei-Lun Hsiao)

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(2015年)

https://doi.org/10.6342/NTU.2015.01287

摘要

據統計，在台灣發生於交叉路口的肇事事故佔總體事故的60%。若進一步調查各肇事類型的成因，可發現因各肇事類型所涉及車流動向不同，對應到影響其發生的道路設計也不相同。因此以路口為單位的肇事分析可能隱藏了各類肇事間的差異性，以致無法具體針對各肇事類型提出成因分析與改善策略，顯現以分支為單位，分析各肇事類型的必要性。另外，以肇事資料為基礎評估道路安全面臨的問題有，肇事資料不完整，輕微事件可能無紀錄、資料所須蒐集時間較長且肇事資料同時也代表所有事件「已發生」。以衝突資料判斷路口安全，能減少資料的蒐集時間，在事件發生前做出主動式安全分析。
本研究以衝突參數後侵佔時間描述三穿越型碰撞交叉撞、右轉側撞與左轉穿越側撞之車流交會，以K平均演算法將路口分支依衝突參數和肇事率分成三風險等級，最後以決策樹CART和隨機森林分析影響分支風險的道路設計因子。
研究結果顯示，後侵佔時間定為3秒適合描述交叉撞與右轉側撞之衝突。在道路設計上，道路交角、路型配置、標線位置、號誌設計等為影響三類肇事的重要變數。同時，本研究也建立了衝突門檻，做為以衝突評估路口分支風險的標準。

關鍵字

路口安全 ； 主動式安全分析 ； 後侵佔時間 ； 資料探勘 ； 肇事因子分析

並列摘要

The conclusion of the past traffic safety study revealed that safety diagnosis and collision factors study on the basis of intersection faced the problem of detail lost for each collision type. It is essential to analysis traffic safety based on collision types and approaches. In addition, safety analysis using collision factors is reactive, the shortcomings include the less damaging collision may not be reported, small data quantity and the analysts need to wait for accidents to take place in order to prevent. Conflict events are more frequent than collisions and it brings complementary information. With surrogate safety measures, the road safety analysis can be proactive.
This thesis presents a collision type based study on approaches using conflict and collision data. K-means algorithm is used to identify risk groups of approaches with similar conflict and collision attribute, decision tree and random forest are used to analyze the relationship between road attribute and risks outcome.
The result shows the effectiveness of post encroachment time as a surrogate measure in right angle collision and right turn with through collision, with the best results at a threshold as 3s. In road design, the decision tree and random forest confirms the importance of collision factors: intersection angle, lane design, road markings and signal timing design. The thesis also established risk thresholds for post encroachment time and conflict rate as a diagnosis tool to evaluate traffic safety of approaches.

並列關鍵字

Traffic safety ； Surrogate safety analysis ； Post encroachment time ； Data mining ； Collision factors

參考文獻

2. Abdel-Aty, M. A., & Radwan, A. E. (2000). Modeling traffic accident occurrence and involvement. Accident Analysis & Prevention, 32(5), 633-642.

3. Alenezi, A., Moses, S. A., & Trafalis, T. B. (2008). Real-time prediction of order flowtimes using support vector regression. Computers & Operations Research, 35(11), 3489-3503.

6. Ang, A. H. S., & Tang, W. H. (1984). Probability concepts in engineering planning and design.

8. Besag, J., York, J., & Mollié, A. (1991). Bayesian image restoration, with two applications in spatial statistics. Annals of the institute of statistical mathematics, 43(1), 1-20.

9. Blumenthal, M. (1967). Dimensions of the traffic safety problem (No. 670011). SAE Technical Paper.