A two-stage short-term traffic flow prediction method based on AVL and AKNN techniques

MENG Meng(孟梦)^{1, 2}, SHAO Chun-fu(邵春福)¹, WONG Yiik-diew(黃育兆)², WANG Bo-bin(王博彬)¹, LI Hui-xuan(李慧轩)¹

(1. Key Laboratory for Urban Transportation Complex Systems Theory and Technology of
Ministry of Education (Beijing Jiaotong University), Beijing 100044, China;
2. Centre for Infrastructure Systems, Nanyang Technological University, Singapore 639798, Singapore)

Abstract:Short-term traffic flow prediction is one of the essential issues in intelligent transportation systems (ITS). A new two-stage traffic flow prediction method named AKNN-AVL method is presented, which combines an advanced k-nearest neighbor (AKNN) method and balanced binary tree (AVL) data structure to improve the prediction accuracy. The AKNN method uses pattern recognition two times in the searching process, which considers the previous sequences of traffic flow to forecast the future traffic state. Clustering method and balanced binary tree technique are introduced to build case database to reduce the searching time. To illustrate the effects of these developments, the accuracies performance of AKNN-AVL method, k-nearest neighbor (KNN) method and the auto-regressive and moving average (ARMA) method are compared. These methods are calibrated and evaluated by the real-time data from a freeway traffic detector near North 3rd Ring Road in Beijing under both normal and incident traffic conditions. The comparisons show that the AKNN-AVL method with the optimal neighbor and pattern size outperforms both KNN method and ARMA method under both normal and incident traffic conditions. In addition, the combinations of clustering method and balanced binary tree technique to the prediction method can increase the searching speed and respond rapidly to case database fluctuations.

Key words:engineering of communication and transportation system; short-term traffic flow prediction; advanced k-nearest neighbor method; pattern recognition; balanced binary tree technique