The accurate visualization of regional public transit is essential for sustainable urban planning and evidence-based policymaking. Many municipalities still face “data deserts” where official General Transit Feed Specification (GTFS) data is unestablished or its publication has been discontinued, while existing dynamic simulation tools often rely on complex, server-side infrastructure that presents high barriers to entry. This study presents a lightweight R-based pipeline that automatically converts static GTFS data into dynamic GeoJSON formats, enabling flicker-free spatiotemporal transit visualization without heavy infrastructure requirements. The pipeline’s efficacy is demonstrated by constructing an integrated, multi-operator regional transit simulator for Chita City, Higashiura Town, Obu City, Japan, and commercial Chita Bus lines. We provide also a diagnostic pilot model for Agui Town, where official GTFS distribution has been discontinued, to illustrate the technical boundaries and structural limitations of third-party data reconstruction. The model delivers empirical evidence for the necessity of institutional GTFS publication by local governments. The pipeline, archived in Zenodo, affords a reproducible platform for the evaluation of regional transit designs and facilitation of collaborative consensus-building. Notice The paper associated with this research/dataset is available on SSRN. The latest version of the preprint, which includes corrected names of the analyzed municipalities and other textual updates, can be accessed here: https://papers.ssrn.com/sol3/papers.cfm?abstract_id=6925698