Step 1: Identify the relevant industry for "VINCI".
VINCI is a global player in concessions and construction, operating significant infrastructure assets such as roads, airports, and rail networks, as well as construction operations. Based on the provided industry methodologies, "Transportation Infrastructure" is the most relevant industry for the concession side of its business, which drives a large portion of its profitability and assets (Service Concession Rights are the largest intangible asset). However, its large contracting segment fits better under a general corporate assessment. We will use the general corporate baseline formulas provided in the steps, while incorporating adjustments (like operating leases) specified in the methodology for infrastructure/concession entities.

Step 2: Estimate the 2021 "Adjusted_EBITDA".
Formula: Adjusted_EBITDA = EBITDA (reported or reconstructed) + adjustment_leases + nonrecurring_losses - nonrecurring_gains ± pension_adjustments ± joint_venture_proportional_EBITDA ± other_normalization_adjustments
- EBITDA = Profit Loss From Operating Activities + Depreciation And Amortisation = 4,438,000,000 + 3,219,000,000 = 7,657,000,000 EUR
- Adjustment for leases (interest on lease liabilities): 43,000,000 EUR
- Nonrecurring losses/gains: Other Operating Income Expense Non Recurring = -26,000,000 (This is a gain, so we subtract it). Subtraction = -(-26,000,000) = +26,000,000 EUR.
- Other normalization adjustments (Share-based payments): 84,000,000 EUR
Adjusted_EBITDA (2021) = 7,657,000,000 + 43,000,000 + 26,000,000 + 84,000,000 = 7,810,000,000 EUR

Step 3: Estimate the 2021 "FFO".
Formula: FFO = Adjusted_EBITDA - cash_interest - cash_taxes
- Cash interest: Gross Finance Costs = 674,000,000 EUR
- Cash taxes: Income Taxes Paid = 1,213,000,000 EUR
FFO (2021) = 7,810,000,000 - 674,000,000 - 1,213,000,000 = 5,923,000,000 EUR

Step 4: Estimate the 2021 "Adjusted_Debt".
Formula: Adjusted_Debt = (reported_debt + leases + pension_deficit + guarantees + hybrid_debt_portion + other_debt_like_items) - eligible_cash
- Reported debt: Noncurrent Bonds (22,212,000,000) + Other Noncurrent Borrowings (2,757,000,000) + Short-term Borrowings (5,769,000,000) = 30,738,000,000 EUR
- Leases: Noncurrent Lease Liabilities (1,574,000,000) + Current Lease Liabilities (524,000,000) = 2,098,000,000 EUR
- Derivative liabilities (debt-like): Noncurrent (422,000,000) + Current (513,000,000) = 935,000,000 EUR
- Total Debt and Debt-like items = 30,738,000,000 + 2,098,000,000 + 935,000,000 = 33,771,000,000 EUR
- Eligible cash: Cash And Cash Equivalents = 11,065,000,000 EUR
Adjusted_Debt (2021) = 33,771,000,000 - 11,065,000,000 = 22,706,000,000 EUR

Step 5: Calculate the 2021 "Adjusted_Debt / Adjusted_EBITDA" ratio.
Adjusted_Debt / Adjusted_EBITDA (2021) = 22,706,000,000 / 7,810,000,000 = 2.907x

Step 6: Calculate the 2021 "FFO / Adjusted_Debt" ratio.
FFO / Adjusted_Debt (2021) = 5,923,000,000 / 22,706,000,000 = 0.261 (26.1%)

Step 7: Estimate the 2022 "Adjusted_EBITDA".
- EBITDA = Profit Loss From Operating Activities + Depreciation And Amortisation = 6,489,000,000 + 3,613,000,000 = 10,102,000,000 EUR
- Adjustment for leases: 48,000,000 EUR
- Nonrecurring losses/gains: Other Operating Income Expense Non Recurring = 8,000,000 (This is a gain, so we subtract it). Subtraction = -8,000,000 EUR.
- Other normalization adjustments (Share-based payments): 162,000,000 EUR
Adjusted_EBITDA (2022) = 10,102,000,000 + 48,000,000 - 8,000,000 + 162,000,000 = 10,304,000,000 EUR

Step 8: Estimate the 2022 "FFO".
- Cash interest: Gross Finance Costs = 750,000,000 EUR
- Cash taxes: Income Taxes Paid = 1,603,000,000 EUR
FFO (2022) = 10,304,000,000 - 750,000,000 - 1,603,000,000 = 7,951,000,000 EUR

Step 9: Estimate the 2022 "Adjusted_Debt".
- Reported debt: Noncurrent Bonds (20,425,000,000) + Other Noncurrent Borrowings (3,205,000,000) + Short-term Borrowings (6,368,000,000) = 29,998,000,000 EUR
- Leases: Noncurrent Lease Liabilities (1,580,000,000) + Current Lease Liabilities (522,000,000) = 2,102,000,000 EUR
- Derivative liabilities (debt-like): Noncurrent (1,939,000,000) + Current (440,000,000) = 2,379,000,000 EUR
- Total Debt and Debt-like items = 29,998,000,000 + 2,102,000,000 + 2,379,000,000 = 34,479,000,000 EUR
- Eligible cash: Cash And Cash Equivalents = 12,578,000,000 EUR
Adjusted_Debt (2022) = 34,479,000,000 - 12,578,000,000 = 21,901,000,000 EUR

Step 10: Calculate the 2022 "Adjusted_Debt / Adjusted_EBITDA" ratio.
Adjusted_Debt / Adjusted_EBITDA (2022) = 21,901,000,000 / 10,304,000,000 = 2.125x

Step 11: Calculate the 2022 "FFO / Adjusted_Debt" ratio.
FFO / Adjusted_Debt (2022) = 7,951,000,000 / 21,901,000,000 = 0.363 (36.3%)

Step 12: Classify the year-on-year credit trend between 2021 and 2022.
Signal 1: Leverage (Change in Adjusted_Debt / Adjusted_EBITDA)
Ratio 2022 (2.125x) - Ratio 2021 (2.907x) = -0.782x
Threshold: ≤ -0.2x implies Improving. The leverage signal is clearly "Improving".

Signal 2: Cash-flow coverage (Change in FFO / Adjusted_Debt)
Ratio 2022 (0.363) - Ratio 2021 (0.261) = +0.102
Threshold: ≥ +0.03 implies Improving. The cash flow coverage signal is clearly "Improving".

Since both signals agree, the credit trend is Improving.

<answer>Improving</answer>