小汽車共乘起源於因應1970 年初的石油危機，為常見的都市運輸需求管理策略之一，其優勢在於善用小汽車空位以改善交通。國內相關共乘研究以探討小汽車共乘的推行可能性以及共乘配對演算法為主，尚無針對國內小汽車共乘族群及路線特性的研究，且小汽車共乘相較於其他運輸工具的市場定位也不明確，往往在政策規劃與制定中被遺漏。 本研究利用全臺最大規模的資訊平台（桃北北宜基共乘網資料庫）進行分析，包含潛在共乘者特性與路線特性兩類，以人文與地理為基礎作市場區隔，並以潛在共乘者平日使用運具了解目標市場，之後將共乘資料庫結合城際運輸模式的旅運資料，探討不同共乘路線之運具方案間的選擇彈性，做為市場定位依據。研究結果顯示： 1. 小汽車共乘的潛在族群以 26-35 歲從事服務業、科技業、製造業為主的男性。 2. 高達 65%的共乘路線旅行時間在30 至60 分鐘，且平均發生在一周內的每個工作日，可判斷共乘主要的市場為城際通勤旅次。 3. 小汽車共乘主要發生在人口密度較低、自行開車較普遍的地區，未來可選擇與都市互動較頻繁的市郊或郊區優先推動。 4. 根據選擇彈性定位分析，小汽車共乘的旅行時間屬性與自行開車相近，而旅行成本屬性偏向費用較低廉的大眾運輸，因此定位為兼具時間與成本競爭力的副大眾運輸，宜持續推動。 Carpooling can be traced back to the oil crisis at 1970s. Taking advantage of vacant seats to reduce private vehicle traffic, carpooling is a commonly seen strategy of urban transportation demand management. Prior studies primarily focused on the feasibility of carpooling or ridematching algorithms, leaving the characteristics of carpoolers and carpool routes unclear. Also, carpool is usually neglected in transportation policy making due to the non-identified market positioning. This study retrieved the database of New Taipei City’s Green Carpool Website－the largest carpool information platform in Taiwan. The characteristics of potential carpoolers and carpool routes were explored as the demographic and geographic basis of market segmentation. Then the market target was identified by analyzing the commuting modes for potential carpoolers. Combining the carpool database and the Intercity Transportation Demand Model formed the choice analysis that revealed the elasticity and positioning of different modes, including carpooling. The findings show that: 1.Majority of the potential carpoolers were aged 26 to 35 years old in the service, technology, and manufacturing industries. 2.Up to 65 percent of the carpool routes had travel time between 30 to 60 minutes in each weekday, indicating the market for carpool is primarily intercity commuting. 3.Carpool demand tended to arise in the low populated area where most people drove alone. Suburban or rural areas with fairly strong connections to cities can be the target for carpool campaign. 4.According to the elasticity positioning analysis, carpooling and driving alone had similar attributes of low travel time, while carpooling and mass transit had similar attributes of low travel costs. Carpooling can be positioned as temporally and monetarily competitive para-transit that is worth promoting.