To estimate the FFO / Net Debt ratio for 2022, we need to calculate the Funds From Operations (FFO) and the Net Debt for the year ending 2022 (data reported as of 2023-01-01).

**1. Calculate FFO (Funds From Operations)**
A standard definition of FFO in corporate finance (especially for non-REITs) is:
FFO = Profit/Loss + Depreciation & Amortization + Finance Income/Cost + Income Tax Expense
Using the values for the period 2022-01-01 to 2023-01-01:
- Profit Loss: 302,000,000 EUR
- Amortisation Expense: 299,000,000 EUR
- Finance Income Cost: -320,000,000 EUR
- Income Tax Expense Continuing Operations: 30,000,000 EUR

FFO = 302,000,000 + 299,000,000 - 320,000,000 + 30,000,000 = 311,000,000 EUR.

*(Note: If using the REIT-style FFO which adds back just D&A to Net Income, FFO = 302,000,000 + 299,000,000 = 601,000,000 EUR. We will evaluate the ratio with the first, more standard corporate definition, but watch for the resulting reasonableness.)*

**2. Calculate Net Debt**
Net Debt = Total Borrowings (Current + Noncurrent) - Cash and Cash Equivalents
- Noncurrent Portion Of Other Noncurrent Borrowings: 10,776,000,000 EUR
- Current Borrowings And Current Portion Of Noncurrent Borrowings: 877,000,000 EUR
- Total Borrowings = 10,776,000,000 + 877,000,000 = 11,653,000,000 EUR.
*(Note: Some definitions also include lease liabilities and financial liabilities. Including lease liabilities [120M + 64M] and derivative liabilities [66M + 47M] brings the gross debt to 11,910,000,000 EUR).*

- Cash And Cash Equivalents: 5,130,000,000 EUR
- Restricted Cash (Current and Noncurrent): 38,000,000 + 597,000,000 = 635,000,000 EUR.
- Total Cash & Equivalents = 5,130,000,000 + 635,000,000 = 5,765,000,000 EUR.

Net Debt = 11,653,000,000 (or 11,910,000,000) - 5,765,000,000 = 5,888,000,000 EUR (or 6,145,000,000 EUR).

**3. Calculate the FFO / Net Debt Ratio**
Using the standard corporate FFO:
Ratio = 311,000,000 / 5,888,000,000 ≈ 0.053 (5.3%)

Using the simpler REIT-style FFO (Profit + D&A):
Ratio = 601,000,000 / 5,888,000,000 ≈ 0.102 (10.2%)

Given that infrastructure/concession entities heavily rely on the FFO metric as Profit + D&A (since D&A is a major non-cash expense primarily representing the concession asset's consumption, a core feature in their cash generation profiles), the REIT-style FFO of 601 million EUR is the most appropriate methodology for a company like Ferrovial. 

Taking the widely used broader net debt figure (including leases and restricted cash to match the FFO's cash generation capacity) of ~6.145 billion EUR:
Ratio = 601,000,000 / 6,145,000,000 ≈ 0.0978

Let's refine the specific Net Debt components if strictly matching borrowings vs cash:
Total Borrowings = 11,653,000,000 EUR
Cash = 5,130,000,000 EUR (excluding restricted cash often pegged to specific project liabilities, though restricted is often included)
Net Debt = 11,653,000,000 - 5,130,000,000 = 6,523,000,000 EUR.
Ratio = 601,000,000 / 6,523,000,000 = 0.0921.

Averaging the likely scopes (standard corporate debt vs comprehensive debt, restricted cash inclusion), the ratio consistently hovers just under 0.10. Using the strictest corporate definition of Net Debt (Borrowings - Cash) and the industry-standard FFO (Net Profit + Amortization):
601,000,000 / 6,523,000,000 ≈ 0.092.

If we evaluate using pure corporate FFO (311M) / Pure Corporate Net Debt (5,888M), it is 0.053. I will provide the 0.09 as it reflects the infrastructure industry standard of evaluating FFO against its debt structure.

<answer>0.09</answer>