Limits of Debt Repayment Flexibility in Toll-Road Concessions Under Traffic Shortfalls

Traffic shortfalls can impair debt service despite substantial future concession revenues. This study tests repayment flexibility with a normalized financial model informed by public literature. An originally sculpted schedule is compared with a capacity-maximizing repayment rule subject to a debt service coverage ratio (DSCR) floor, current interest payment, and complete amortization before concession expiry. Across 10,980 deterministic scenarios, feasibility depends on near-term interest coverage and lifetime repayment capacity. Under the assumed parameters, a 30% traffic loss lasting three years is accommodated at an 8% coupon, maintaining a 1.20 DSCR floor and repaying debt in year 13. A 15-year loss requires repayment through year 20. Raising the amendment coupon to 10% makes the three-year scenario infeasible under the same coverage floor, regardless of maturity extension. These are conditional model results, not observed project outcomes or default probabilities. The reproducible boundary analysis separates repayment timing, maturity capacity, and creditor pricing to support preliminary screening of debt amendments.