中古車市場的動態模擬：代理人基建模方法之應用
池秉聰、楊志華
摘要
儘管中古車市場的成交量在最近十多年來不斷激增，但影響消費者在決定購買中古車時最大的因素，就是中古車的價格及品質。另一方面，中古車市場車商的素質沒有統一的品質認定標準可供參考，在此情形下，如何鑑別車輛的品質對買方是非常重要的事。過去有些不肖中古車商不重視消費者使用安全性，唯利是圖枉顧消費者權益，違法販售事故車、泡水車、變造車及問題車輛，使得買方對中古車產生不信任感及不安全感，造成阻礙中古車市場成長的要素，更是中古車市場無法正常運作與發展的主因。由於資訊不對稱，消費者在中古車市場上對品質的質疑及不安全感，產生劣幣驅逐良幣的現象， Akerlof (1970) 指出中古車市場將充斥檸檬車(lemon car)的市場失靈現象。由於消費者權益無法受到合理的保障，亦時常造成買賣糾紛。然而，中古車市場並未消失，一方面，業者努力解決資訊問題，例如中古車保證售後服務、認證及檢查系統；另一方面，Kim (1985) 指出中古車市場的資訊不對稱下仍然存在均衡。本研究以 Kim (1985) 的模型出發，建立一個動態的中古車市場模型，考慮資訊不對稱、車輛的耐用年限、折舊、消費者所得與偏好、中古車商、新車製造商的策略，研究中古車市場的成功條件及廠商競爭的動態。本研究將以模型驗證此趨勢及分析未來的產業發展。
關鍵詞：資訊不對稱、中古車市場、檸檬車、市場失靈、代理人基建模
The Dynamics of Used Car Markets: An Application of Agent-Based Simulation
Bin-Tzong Chie and Chih-Hwa Yang
Abstract
Although used car market has grown rapidly over two decades in Taiwan, quality and price are the main criteria that consumers concerned when buying a used car. Due to lack of a used car certified standard, the reputation among car dealers varies. How to verify the quality of used cars is a crucial factor for buyers. Two decades ago, some unethical used car dealers sold vehicles with hidden issues, for instance, accidents or damage vehicles. These problems had restrained the growing of used car markets. Akerlof (1970) pointed out that the used car market will be failure due to the information asymmetry. The quality uncertainty makes consumers’ rights in the used car market cannot be reasonably protected, and often causes disputes after sales. Kim (1985) suggested that the information asymmetry in the used car market is not only limited to the used car buyers, but also many individual used car sellers. Inspired by the model of Kim (1985), this study established a dynamic model of a used car market. The model considered information asymmetry, the life of the vehicle, depreciation, consumer income, preference, the strategies of the used car dealers and new car manufacturers to identify the business model and the competition advantage of used car industry. This study will validate the trend with agent-based models and analyze the future of used car dynamics.
Keywords: Information asymmetry, Used car market, Lemon car, Market failure, Agent-based modeling
Received: 2017-12-27
Accepted: 2018-03-26