Did UberX reduce ambulance volume?
研究UberX进入城市后，是否替代了低风险患者的传统救护车使用，发现其使人均救护车使用量至少减少6.7%，对政策制定者和医疗保险公司有参考价值。
Ambulances are a vital part of emergency medical services. However, they come in single, high intervention form, which is at times unnecessary, resulting in excessive costs for patients and insurers. In this paper, we ask whether UberX's entry into a city caused substitution away from traditional ambulances for low-risk patients, reducing overall volume. Using a city-panel over-time and leverage that UberX enter markets sporadically over multiple years, we find that UberX entry reduced the per capita ambulance volume by at least 6.7%. Our result is robust to numerous specifications.