利用運輸路網可靠度評估先進旅行者資訊系統之價值

Abstract

隨著科技進步，民眾重視交通需求的層面從縮短旅行時間，逐漸轉變成旅行時間的準確程度。然而，路網系統具有不確定因素存在，這些不確定因素會影響路網使用者的帄均旅行時間，也影響了系統的總旅行時間。為了評估或預估路網是否能滿足使用者的需求，路網可靠度是一個具代表性的衡量指標。 另一方面，智慧型運輸系統中的先進旅行者資訊系統 (ATIS) 也越來越發達，其功能與發展程度也日益增加。該系統能提供使用者路網資訊，當路網系統受損時，使用者能依據資訊系統提供的建議，減少旅行成本的額外增加。 本研究依據路網使用者是否具備ATIS系統將使用者分群，建立多層級使用者 (multiple user class)。透過蒙地卡羅模擬方法 (Monte Carlo technique) 進行交通路網指派 (traffic assignment)。研究採用之交通路網指派方法包含使用者均衡模式 (UE) 與隨機使用者均衡模式 (SUE)，建立不同類型使用者的路徑選擇模式。 研究中將利用路網可靠度 (network reliability) 做為評估指標之一，觀察ATIS系統為路網系統帶來的效益。在研究中發現，ATIS系統對使用者的帄均旅行時間改善傴在有限的使用者比例內；而透過路網可靠度則可更進一步的衡量ATIS系統對使用者的效益所在。

With advances in technology, the people extend their attention from receiving travel time information to the concern about the accuracy of the travel time information, which may be affected by many uncertainty factors such as traffic accidents, incidents, or variations of daily travel demand. The level of penetration of information and the response of travelers will in turn affect individual user's travel time and as well the total travel time of the system. In order to assess if the transport network could meet the travel demand in terms of probability, reliability of transport network is a representative measurement indicator. Reliability of transport network is a topic in Advanced Traveler Information System (ATIS) of Intelligent Transportation Systems. Considering car navigation with real-time information is an application, if the system could provide information about traffic to users who is driving on the road, it is possible to divert the users, so as to reduce traveling cost. This is even pronounced when the traffic network system is degradable. In this research, users are divided into two classes for analysis: ATIS equipped users and non-ATIS users. Two models are developed to investigate the proposed problem. In the first model, traffic assignment model for multiple user classes is used, where traveler’s route choice behavior is in User Equilibrium (UE), and Monte Carlo simulation technique is used to simulate the daily variation of road capacity. The second model is a Stochastic User Equilibrium (SUE) formulation which can model the differences of information perceptions between the two groups of users. Reliability of transport network is taken as an indicator in this research. With the results of simulation, ATIS system can improve the travel time of all users in the network, but the advantage of ATIS users over non-ATIS users is diminishing as the number of ATIS users (i.e. market penetration) increase.