Roads and bridges constitute the largest category of public infrastructure investment in India and increasingly rely on private capital mobilised through BOT, HAM, and DBFOT structures. Despite a mature policy framework anchored in the Model Concession Agreement, the sector continues to witness cost and time overruns, contract renegotiations, and premature concession terminations—largely traceable to inadequate pre-financial-closure due diligence. This paper develops and empirically applies a structured Due Diligence Assessment Instrument (DDAI) integrating six dimensions: technical/engineering, financial/commercial, legal/contractual, environmental/social, regulatory/statutory, and risk/contingency. The instrument was validated through a two-round Delphi exercise with twelve domain experts and weighted using the Analytic Hierarchy Process (AHP). Application to two illustrative case packages—a road-widening BOT/HAM package (Case A) and a major bridge construction package (Case B)—surfaced sixty-four red-flag findings, dominated by land acquisition and right-of-way (28%), design and geotechnical uncertainties (19%), and contractual/legal ambiguities (16%). A simulated cost-trajectory comparison indicates that structured due diligence embedded before financial closure can materially compress the cost-escalation envelope. The paper concludes with recommendations for institutionalising structured due diligence within existing NHAI/State Highway Authority appraisal workflows.

Ram Prakash Singh, Mr. Rajesh Joshi,"A Structured Multi-Dimensional Due Diligence Assessment Instrument for Indian Road and Bridge Infrastructure Projects: Design, Weighting, and Case Application" International Journal of Advanced Multidisciplinary Research and Educational Development, V2(5): Page(781-788) September - October 2026. ISSN: 3107-6513. www.ijamred.com. Published by Scientific and Academic Research Publishing.