考量街道寧適性下步行可及性與移動性之研究

Abstract

近年來，街道改善計畫常藉由提升街道空間寧適性以提升視覺、心理愉悅度進而提升步行意願，其對行人生理機制之影響亦受到關注，特別是當今社會高度重視步行對健康之效益。行人廊道為都市中常見的線型步行空間，主要用於進出交通場站或抵達鄰近活動發生點，其規劃設計議題大多聚焦在容量設計上，然而近年研究發現平面設計型態亦會影響行人流量。再者多數已開發國家未來都須面對人口老化問題，低速度的老年行人使用大眾運輸系統比例將增加，廊道內步行移動性差異逐漸擴大，增加碰撞與局部擁擠發生機率。 對此本研究分別從心理與生理量測法分析街道寧適性對步行可及性以及廊道空間平面設計對步行移動性之影響。以行人路權、夜間照明、綠美化、街道傢俱、沿途商業活動、鋪面以及水景等七個街道空間元素為主要寧適性因子，分別從心理與生理的角度探討街道寧適因子變動下對步行意願與距離之影響。心理層面同時設計顯示性與敘述性偏好問卷，調查不同起迄對步行路線選擇行為，以降低各因子共線性並提高資料變異度，校估步行效用函數，進而觀察各寧適性因子變動下對步行意願與距離之影響。生理層面則透過實驗設計，加入上述因素之影響，改善並應用Pandolf et al.(1977)模式於捷運旅客步行能量消耗之調查，進而從能量分布函數推導出各街道空間下之步行可及距離。為確保步行安全性與系統效率，提升民眾步行意願，本研究以Helbing et al. (2000)模式為基礎，並透過行為觀察構建步行模式，從真實案例歸納出六種替選方案，應用C語言設計代理人模擬程式，探討可有效提升行人流速的平面設計手法。 結果顯示綠美化與商業活動對於步行意願具有正效應，步行時間則為負效應，亦即規劃者在進行街道改善計劃時可優先從綠化與沿街商業活動著手改善；行人路權在敍述性偏好中具有極顯著的效應，但在顯示性偏好中則為不顯著，代表實際行為與假設性意願存在差異；另外，照明設計與街道傢俱手法，對於提升步行意願皆為不顯著。生理層面部分，經能量消耗實驗校估出Pandolf et al.(1977)修正模式，應用於能量計算以求得次數統計並進行適配度檢定，結果發現步行能量消耗呈現Gamma分布，意謂行人於通勤旅次中普遍追求節能、省力之特性。應用花台進行中央分隔與推廣低速度行人靠兩側行走可有效提升行人流速；若應用座椅區隔出老人專用空間，雖然提高安全性卻大幅降低有效寬度，影響年輕行人之步行速度。本研究結果成果可提供規劃者從事步行可及性指標制定、街道改善方案評估以及步行行為分析之參考依據，也進一步解釋為何規劃者多傾向採用全開放式空間，但透過集體行為規範同樣可提高系統效率而又不影響廊道的有效寬度。

How to improve street amenities (SA) to both raise willingness to walk (WTW) and level of service (LOS) is a crucial issue for planners when designing a pedestrian-friendly environment in terms of accessibility and mobility. However, few studies have provided rigorous and systematic analysis to aid this practice. Thus, this research addresses this issue with three topics: first, defining measures of WTW to represent variation across environments; second, estimating WTW for the varied levels of SA; third, designing the arrangement of SA to raise LOS when mobility difference is high. Attributes of street amenities are classified, such as right of way, lighting, planting etc., and WTW is defined with both physiological and psychological measure: energy expenditure (EE) and walking time. The WTW measures taking into account the effects of SA are estimated by designing energy expenditure and conducting revealed and stated route choice experiments. The Pandolf et al. (1977) model is used to analyze the walking energy expenditure (WEE). The terrain factor is adjusted using the calibrated regression function to fit the urban street space in the experiment. To avoid violation of the irrelevance of independent alternatives (IIA), random-parameters logit is applied to build route choice model. With respect to nature of pedestrians and data scale, Helbing’s (2000) agent-based model is modified to model passing behaviors. The simulations are conducted with the designed simulator at Fruin’s (1971) six levels of flow to fully represent pedestrian flow. Results show that WEE sample suggests a Gamma distribution. The accessible walking distance pattern around a service facility should be designed based on the service contour lines which take into account the effects of SA. Results of pedestrian route choice show improvement for right of way, lighting, planting, retailing, and fountains, would significantly enhance WTW. The results of ABM indicate that a corridor in which a line of round objects, such as potted plants, are positioned to divide a bidirectional stream of pedestrian traffic, can result in a relatively smoother flow than if the objects were rectangular in shape, e.g., benches. It is worth noting that by promoting collective self-organizing when it comes to walking direction, and by providing a sub-lane along the wall for slower walking, a better performance can be obtained, even without reducing the effective width.