以GPS數據探討影響機車平均速度的環境因素

Abstract

機車曾被認為是過渡到汽車時代的產物，最終會隨汽車的大量製造與使用而遭淘汰，然而，因其本身的特性與我國特殊的歷史背景，現今仍是我國主要使用的交通工具之一。隨著機車數與使用量的上升而衍伸的各種議題，以討論機車速度最為豐富與廣泛。機車速度影響著道路的服務水準，速度太慢將使效率降低，速度太快又可能引發交通事故。回顧當前文獻大多著重在機車騎士本身的特徵與態度、不同機車種類與外型或是道路硬體的設計對於機車速度的影響，並且都是從小尺度、短時間的微觀視角切入，缺乏空間與時間上巨觀的討論。因此，本研究以機車為主體，以臺北市共享機車全球定位系統紀錄作為研究資料，應用階層線性模式(hierarchical linear modeling, HLM)處理環境與道路兩層次之巢狀資料結構，探討機車平均速度與道路因素、環境特徵之間的關係、原因以及時間上的差異。 實證結果發現，道路與環境特徵皆對機車平均速度有顯著性影響，且此影響關係因時段不同而有所差異。道路寬度對機車速度的影響為負，公車站位數、汽車停車格數、行駛於主要道路則為正，有測速照相機與行駛於服務道路在部分時段亦為正。環境特徵變數方面，人口密度在各時段為負，純住宅土地使用比例在部分時段為正，學校則在平日日間尖峰時段為負，顯示當前學校周邊之交通措施(諸如安排導護志工、劃設交通寧靜區)創造了更為友善與安全的上學環境，而純住宅區則是相對潛在不安全的地方。研究結果亦發現，道路因素對機車速度以直接影響為主，而環境因素則扮演著間接影響的角色，並且商業區環境調節道路特徵對機車速度，住宅區則直接影響機車速度。本研究在學理上補充了機車速度與土地使用之關係，在實務上亦能提供政府部門作為機車管理政策規劃之參考，建立安全友善的生活環境。

Scooters were regarded as a temporary means of transportation before automobiles were widely used. However, due to the characteristics of scooters and the special historical background of our country, they are still one of the main means of transportation used in Taiwan currently. With the increases of ownership and usage of scooters, more and more scooter-related studies have emerged. Of these studies, scooter speeds are the most frequent topics. Driving speeds of scooters are related to level of service on roads. Decreasing speeds reduces efficiency, while increasing speeds may cause traffic accidents. Most of the previous studies in literature focused on the influences of characteristics of scooter riders, types of scooters and road geometric design on scooter speeds, and neglected the macroscopic considerations of spatial and temporal attributes. Therefore, this study used the GPS data of scooter-sharing rental records in Taipei City as the research data and applied hierarchical linear modeling (HLM) method to investigate the relationships between average speeds of scooters and attributes of road and environment. The empirical results reveal that both road and environmental characteristics have significant effects on average speeds of scooter, and these effects vary from time to time. Scooter speeds are negatively related to road width and positively related to the number of bus stops, car parking spaces and primary roads. The presence of speed cameras and local roads are positively related to scooter speeds during some periods. Among the environmental characteristics, scooter speeds are negatively related to population density during all periods, positively related to proportion of pure residential land use during some periods, and negatively related to proportion of schools during peak hours of daytime on weekdays. This shows that current transportation measures around schools (such as the arrangement of crossing guards and the designation of traffic calming zones) create a more friendly and safe school environment, whereas pure residential areas are relatively potentially unsafe places. Moreover, the empirical findings of this study suggest that the road attributes perform direct effects on speeds, while the environmental attributes play an indirect role. It was also found that the commercial areas moderate the influences of road characteristics on speeds, while residential areas directly affect speeds. This study adds the knowledge of relationships between scooter speeds and land uses to literature and also help administrations to develop scooter management policies and planning for establishing a safe and friendly living environment.