The relation between price and transport demand is one of the main aspects of transport mode choice. While price elasticities are well known for conventional transport modes like driving or public transport, only few studies exist dealing with fares and prices for rather new (shared) modes like bike sharing. In particular, hardly no evidence is available on the impact of the usage fee on trip demand for urban bike share systems. Therefore, the present paper develops an empirical approach to estimate the impact of a temporarily introduced 30-day free bike share rides promotion in Boston, MA in summer 2022. Based on daily trip data of bike sharing systems in Boston, MA and Washington, D.C., a difference-in-differences model is estimated to analyze the impact of the free fare. Results show that trip demand rise by up to 55% due to the waived usage fee during the time of the promotion. Furthermore, model results reveal that trip demand stays at a 20% increased level even three months after the end of the fare free program.

价格与运输需求之间的关系是运输方式选择的主要方面之一。虽然驾驶或公共交通等传统交通方式的价格弹性是众所周知的，但只有很少的研究涉及自行车共享等相当新的（共享）模式的票价和价格。特别是，几乎没有证据表明使用费对城市自行车共享系统出行需求的影响。因此，本文开发了一种实证方法来估计 2022 年夏季在马萨诸塞州波士顿临时推出的 30 天免费共享单车促销活动的影响。基于马萨诸塞州波士顿和华盛顿特区的自行车共享系统的每日出行数据，估计双重差分模型来分析免费票价的影响。结果显示，由于促销期间免收使用费，出行需求增长高达 55%。此外，模型结果显示，即使在免费计划结束三个月后，出行需求仍保持 20% 的增长水平。