考量C型路權路段之輕軌容量模式研發

現代輕軌系統具備靈活的特性，可因應不同環境採取不同的設計，一條路線也可同時包含A、B、C 型等不同的路權型式，其中混和車流的C 型路權路段常是系統瓶頸所在。近年來，國內外許多大都會投入高成本建設並推動輕軌系統的同時，有必要在考量公路車流以及輕軌系統的特性下，以路線容量為指標，評估C 型輕軌系統的最大運輸效能。然而，過去以容量角度切入分析的文獻相當有限，針對輕軌者多半限定於B 型路權的探討。有探討C 型路權容量的多為公車相關之容量研究，然兩種運具畢竟特性不盡相同，無法直接套用。C 型路權之輕軌系統，其潛在容量瓶頸落在C 型段內車站以及兩端折返點。有鑑於此，本研究提出一個完整計算架構，包含七個解析模型，對應到三種C 型路段內的車站以及四種折返模式。模型考量車站佈設、折返點股道運用、公路號誌時制、共用車道小客車車流等條件，求取在前述條件下能通過路線上一點的最大輕軌數量，並可直接套用於一條包含C 型路權路段的輕軌路線。本研究所提之模型，經由VISSIM 軟體模擬驗證，整體MAPE 值為7.81%，顯見精準度足以供輕軌營運者或交通工程師於規劃新系統及系統改良計畫時之參考。

關鍵字

輕軌；路線容量； C型路權；號誌化路口；交通流量

並列摘要

Modern light rail is an urban transportation mode widely adopted by cities in the world recently. It features its flexibility to comprise sections with different rights-ofway. Sections that share the lane with other modes are often bottlenecks of the line. As a result, it is essential to calculate capacity as an indicator to reflect the transportation capability of light rail system with C-type right-of-way. However, past studies mostly focus on light rail with B-type right-of-way. Studies on bus capacity do provide models for transit with C-type right-of-way that give some clue on the location of bottlenecks, but cannot be directly applied because the two types of vehicle bear different characteristics. Throughout the line, stations within C-type right-of-way, along with the turnback points, are bottlenecks constraining the capacity of the system. Consequently, this research proposes a complete computation framework containing seven analytical models corresponding to seven types of potential bottlenecks. The seven types include three types of stations with C-type right-of-way, and four types of turnback operations. The models calculate line capacity under specific station layout, track utilization at turnback point, road traffic flow rate, signal timing at intersections. Theoretical results are validated using traffic simulator VISSIM. The overall MAPE is 7.81% for all scenarios, indicating a reasonable prediction. The proposed models can help operators and traffic engineers to develop efficient plans in new construction or improvement projects.