以運輸多樣性觀點建立都市永續運輸評估與資源分派模式

Abstract

運輸系統中不同權益關係人對於設施與服務有多元之需要，要滿足這些需求必須在供需及本益間進行權衡考量，過程中產生了運輸多樣性之課題，然而過去文獻鮮少提及運輸多樣性相關議題。因此，本研究建立一評估運輸多樣性以改善生活品質之架構，運輸多樣性定義為權益關係人需求被滿足之程度，且利用Shannon-Weaver指標（或稱之為熵）分析各需求現況與期望水準間落差衡量之。運輸多樣性可評估重要之需求是否公平地被滿足，並藉由目標值與基本生活水準之確認以監測運輸系統是否朝向永續發展。本研究所提架構認為評估運輸多樣性時應同時考量多元運輸需要，包括機動性、經濟健全度、可靠度、安全性、可及性、可負擔性、通用化設計程度、外部性及資源超限利用，且不可忽略不同權益關係人，如不同運具使用者、特殊需求使用者及非使用者之需要。因此，在考量生活中運輸需求與旅運行為時，運輸多樣性係達成永續發展及改善生活品質之必要條件。本研究冀望所研提運輸多樣性之概念架構得以協助決策者了解運輸多樣性與永續性之關係，並提供嶄新之評量方法以提升生活品質。 確認權益關係人需求後，本研究歸納文獻相關量化指標以利後續分析進行，並利用大臺北都會區2000年及2005年資料進行時間與空間分析，以探討運輸多樣性評量架構之可行性。縱軸分析結果顯示研究範圍之運輸多樣性有所改善，尤以安全性及可靠度之水準提升最為明顯，但污染排放、可及性及通用化設計水準之提昇則乏善可陳。根據運輸多樣性評量架構之分析結果，決策者得以採取較佳之資源配置策略，例如應更有效地改善交通能力弱勢使用者運輸生活之不便。 此外，資源配置策略可協助規劃者決定投資運輸設施或服務之時機與方式，然而，由於運輸系統中各要件間之關係存在複雜性、不確定性與回饋機制，改善運輸多樣性之資源配置策略之研擬、執行與量化皆相當困難，本研究統整量化之系統動態模型、質化之認知圖法及準量化之感受性模型之特性，建構一整合式系統模擬模型以克服上述問題。透過敏感度分析，顯示私有運具旅次之增加將使能源消耗、污染排放及肇事率加劇，導致運輸多樣性之下降。但政策執行後，其影響不論為即時或有所延滯，皆未顯著影響系統行為與表現。而模擬結果顯示，權益關係人需求滿意度之現況與期望水準間的落差與運輸多樣性存在反向關係，卻與私有運具旅次數成正比。這為提升大眾運輸旅次數可有效彌平使用者需求滿意程度之落差提供了有力之驗證。 根據上述整合性系統模擬模型所界定之運輸系統關係，本研究藉由以柏瑞圖最適理論為基礎之模糊多目標規劃法，解決非線性多目標問題，並以大臺北都會區大眾運輸系統為簡例，同時考量滿意度落差與運輸多樣性，進而探討資源配置對於權益關係人需求滿意水準之影響。由於同時考量滿意度落差與運輸多樣性，此一模式可避免無效率與不公平之資源配置。此外，分析結果顯示近年來大臺北都會區配置在大眾運輸間之投資，已同時考量捷運及公車權益關係人需求滿足程度之公平性，因而使運輸多樣性有所提升。

Different transport stakeholders have different needs for transport infrastructure and services. Meeting the needs of stakeholders implies a trade-off of benefits and costs between supply and demand and creates issues of transport diversity. However, the literature has largely ignored these issues. This study aims to provide a framework evaluating transport diversity to promote quality of life. Transport diversity is defined as the satisfied level of stakeholder needs in this study and measured as the gap between expected goal and present values of stakeholder needs in the form of the Shannon-Weaver Index, or namely the Entropy. Transport diversity can assess whether the level to which important needs are satisfied equitably, and monitor whether the transportation system is moving towards sustainability via confirming the targets and the basic level of quality of life. The proposed framework suggests that the evaluation of transport diversity should consider distinct transportation needs, such as mobility, economic health, reliability, safety, accessibility, affordability, level of universal design, externality and resource over-utilization, of different stakeholder including various modal users, specific users and non-users simultaneously. Accordingly, transport diversity is thus the necessary condition for quality of life and sustainability. Improving the sustainability and quality of life with regard to transportation requires the support of transport diversity. This study hopes that the conceptual framework developed can assist decision-makers in understanding the relationship between transport diversity and sustainability, and provide a new assessing method for improvements in quality of life. After identifying the appropriate indicators referring to stakeholder needs, a preliminary spatiotemporal analysis is illustrated through an empirical study to discuss the managerial implications in the Taipei metropolitan area. The results reveal that transport diversity is improved from 2000 to 2005. In fact, the transportation system has progressed in the satisfactions of safety and reliability. However, the achievements of emission, accessibility and level of universal design perform poorly. Decision-makers could understand better resource allocation policies according to the analytical results. In particular, deficient quality of life for disable users should be improved effectively and efficiently.

Additionally, resource allocation policies help planners decide when and how to invest transportation infrastructure and services. However, policies for improving transport diversity are difficult to design, implement, and quantify because of the uncertainty, feedback interaction, and complexity of system relationships. This study proposes a hybrid model integrating system dynamics, cognitive maps, and sensitivity model to tackle the problems. Notably, the result of sensitivity model reveals that the increment of private vehicle trips reduces transport diversity due to the increase of energy consumption, emission and accident rate. However, tuning policy delays does not significantly impact system performance through managerial choices of resource allocation. Moreover, the simulation results indicate that the gaps in stakeholder needs are generally opposite to transport diversity and positive proportion to private vehicle trips. This verifies that increasing public transit trips helps the system bridge the gap between user satisfactions of stakeholder needs. According to the system relationships constructed by the hybrid systematic simulation tool, fuzzy multi-objectives programming, a Pareto based mathematical approach is employed to solve the non-linear multi-objectives problems focusing on urban public transit systems for determine the impact of resource allocation on need satisfactions related to stakeholder behaviors. The proposed approach evades inefficient and inequitable resource allocation. Furthermore, analytical outcomes show that recent investments allocated to public transit system considered equitable stakeholder satisfactions both of MRT and bus, as well as promoted transport diversity in the Taipei metropolitan area.