RAPID: Fare Free Public Transportation - A Full Scale Natural Experiment in Alexandria, Virginia

这一快速反应研究拨款(RAPID)项目将评估免费公共交通和改善网络连通性对乘客量、私家车行驶里程、温室气体和常规污染物排放、拥堵和交通的影响，并将研究其对不同收入群体和种族的分配影响。该项目基于在弗吉尼亚州亚历山大市进行的一项全面的自然实验，当地交通机构DASH(驾驶亚历山大安全回家)决定在其服务区域内实施免费公共交通计划，主要是出于公平和公平的考虑。这种自然实验将基于对研究区域和一个或多个控制点的数据收集--在计划到位时，并在计划实施前的一段适当时期内进行回顾--以适当评估其成就和效果。调查计划将包括DASH系统的使用者以及治疗地点的普通公众成员，以了解实际或潜在的出行、一般出行模式，以及免费票价是否取代了私家车的出行和排放，或其他交通方式。数据收集计划将辅之以对控制地点的公交用户和普通公众进行的平行调查，以获得类似的信息以及他们打算在巴士免费时使用公交的情况。这项研究及其结果可能会影响政策建议和基础设施投资决策，这将影响我们交通系统的未来和美国公民的生活质量。这一项目的影响在这个时候尤其重要，此时交通使用正在从大流行中缓慢恢复，尚未达到大流行前的乘客量和出行模式份额，而且政府和国会正在考虑为基础设施提供大规模资金。从方法论的角度来看，这项研究涉及在抽样、分析和模拟来自概率和非概率样本的数据方面具有挑战性的统计程序。挑战包括抽样权重的构建、控制地点的选择、确保有效统计推断的处理对象和对照对象的匹配以及许多其他问题。一个由工程学、经济学、调查方法学和数学专业的教师和学生组成的多学科团队将在调查设计、数据链接、计量经济学模型估计以及出行行为和政策分析方面进行合作。该项目预计将作为其他地方类似项目的概念验证，并将为许多实施创新政策计划以增加客运量和可达性的交通机构提供参考。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This Grant for Rapid Response Research (RAPID) project will assess the effects of free public transit and improved network connectivity on ridership, miles driven by private vehicles, emissions of greenhouse gases and conventional pollutants, congestion and traffic, and will study its distributional effects on different income groups and ethnicities. The project is based on a full-scale natural experiment conducted in Alexandria, Virginia, where the local transit agency DASH (Driving Alexandria Safely Home) has decided to implement a fare-free public transportation program over its service territory, motivated primarily by fairness and equity considerations. Such a natural experiment will be based on a data collection the study area and from one or more control locations—while the program is in place, and retrospectively for a suitable period before its implementation—for a proper assessment of its accomplishments and effects. The survey plan will involve both users of the DASH system as well as members of the general public at the treatment location to understand actual or potential travel, general travel patterns, and whether the fare free has displaced private car travel and emissions, or other transportation modes. The data collection plan will be complemented with parallel surveys of transit users and members of the general public at the control locations to elicit similar information and their intended use of transit if the bus became free. This research and its results may influence policy recommendations and infrastructure investment decisions that will impact the future of our transportation system and the quality of life of citizens in America. The impacts from this project are especially relevant at this time, when transit use is slowly recovering from the pandemic and has not yet reached pre-pandemic ridership and travel mode shares, and when large-scale funding to infrastructure is being considered by this Administration and the Congress.From a methodological perspective, the study involves challenging statistical procedures in terms of sampling, analyzing, and modeling the data from both probabilistic and non-probabilistic samples. Challenges include the construction of sampling weights, the selection of control location, matching treated and control subjects to ensure valid statistical inference, and many others. A multi-disciplinary team composed by faculties and students in engineering, economics, survey methodology and mathematics will work collaboratively on survey design, data linkage, econometric model estimation, and travel behavior and policy analysis. The project is expected to be serving as a proof of concept for similar programs elsewhere and will be a reference for the many transit agencies implementing innovative policy schemes to increase ridership and accessibility.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.