Do Major Urban Highway Megaprojects Improve Metropolitan Travel-Time Performance? Evidence from Synthetic-Control Evaluations across U.S. Metropolitan Areas

This package provides the full data, code, and figures needed to reproduce a comparative ex-post appraisal of five major U.S. urban freeway/interchange megaprojects (Atlanta Transform 285/400, Houston I-69/I-610 West Loop, Denver Central 70, Indianapolis I-65/I-70 North Split, Chicago Jane Byrne Interchange), using path-matched synthetic control on the FHWA Urban Congestion Report (UCR) Travel Time Index panel with in-space placebo inference. Contents: 01_Data/ — the balanced FHWA UCR metro-quarter panel, per-city synthetic-control paths, donor weights, placebo distributions, leave-one-donor-out sensitivity, and the cross-city summary estimates 02_Code/ — parse_ucr_quarterly.py (parses source UCR PDFs into the panel) and build_scm_replication.py (runs the SCM estimation, placebo inference, and figure generation end-to-end) 03_Metadata/ — machine-readable summary estimates and article highlights 04_Figures/ — all manuscript figures and the graphical abstract, as PNG, PDF, and 600-dpi TIFF Primary estimator: path-matched synthetic control with in-space placebo inference; primary estimand is the average treatment effect on the treated (ATT) over a common eight-fiscal-quarter post-opening horizon, with full-available-post-window estimates reported as a robustness check. To reproduce: install requirements.txt, then run python build_scm_replication.py from 02_Code/ (or --docs-from-cache to rebuild figures from the archived estimates without re-running optimization). This is a code-and-data replication deposit only; it does not include the manuscript text.