為了減少擁擠的都市交通和提高公共運輸效率，支援智慧交通服務的基礎設施已經是智慧型運輸系統(Intelligent Transport System，ITS)的成功關鍵因素。例如歐盟執行委員會在2017年所發布的歐洲合作智慧型運輸系統(C-ITS)發展和運營政策就計畫於Phase II時發展車路聯網與交通事故告警推播的應用，相關發展智慧型運輸系統的應用還包含了對於公共運輸的大眾運輸號誌優先(Transit Signal Priority, TSP)、緊急車輛號誌搶先(Emergency Vehicle Signal Preemption, EVSP)、適應性號誌控制(Adaptive Traffic Signal Control, ATSC)等，這些應用被認為是一個可持續性發展的城市及智慧城市的重要指標之一。

在這些智慧型運輸系統的應用中，包含大眾運輸號誌優先、緊急車輛號誌搶先、適應性號誌控制、節能駕駛與道路安全應用，都需要透過車載端與路側端的協調控制(Coordinated Control)才能達到各項應用功能。然而現有的研究多半聚焦於單一智慧交通應用的最佳化，卻沒有討論多種應用的轉換與運作模式，因此導致未來在智慧交通的應用上可能會發生衝突問題。

本篇研究基於車載行動網路(Vehicular Network)技術，提出一套智慧交通控制系統(Smart Traffic Signal Control System, STSCS)的軟體與硬體架構，使系統可解決多種智慧交通應用衝突，並且提出緊急車輛號誌搶先之演算法與實作其功能。本系統可相容於現號誌控制器系統，讓相關智慧交通應用能夠真正落實於我國實際的路口上，使號誌設備成為多功能智慧化之路側設備，期望能帶領台灣邁向車路聯網時代。

Infrastructure supporting vehicular network (V2X) capability is the key factor to the success of smart city because it enables many smart transportation services. In order to reduce the traffic congestion and improve the public transport efficiency, many intelligent transportation systems (ITS) need to be developed.

In this paper, a smart traffic signal control (STSCS) system is designed and implemented, it supports several smart city transportation applications including emergency vehicle signal preemption (EVSP), public transport signal priority (TSP), adaptive traffic signal control (ATSC), Eco-driving supporting, and message broadcasting. The roadside unit (RSU) controller is the core of the proposed STSCS, where the system architecture, middleware, control algorithms, and peripheral modules are detailed discussed in this paper.

It is compatible with existed traffic signal controller so that it can be fast and cost-effectively deployed. A new trac signal scheme is specially designed for the EVSP scenario, it can inform all the drivers near the intersection regarding which direction the emergency vehicle (EV) is approaching, smoothing the traffic flow, and enhancing the safety. EVSP scenario and the related control algorithms are implemented in this work; integration test and field test are performed to demonstrate the STSCS.

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