Tax Authority and Traffic Cross Vehicle Data: What Risk Do You Have in 2026

Key data

The Tax Authority and Traffic have expanded and updated their information-sharing agreement to strengthen the detection of tax fraud. The amendment published on April 20, 2026 modifies the original agreement between the State Tax Administration Agency (AEAT) and the Autonomous Body Central Traffic Authority, and came into force on April 10, 2026.

The practical result is clear: the Tax Authority now has enhanced and updated access to the vehicle registry to cross-reference it with what taxpayers declare. Any inconsistency between vehicle ownership and the declared tax situation can trigger a request for information or an inspection.

What does this regulation establish?

The amendment modifies the original agreement between the AEAT and the Central Traffic Authority in two main dimensions:

• Technical and legal update: The terms of the agreement are adapted to current data protection and electronic administration regulations, allowing for more agile and secure information exchange between both organizations.
• Strengthening of cross-data analysis: The AEAT accesses data on motor vehicle ownership from the Traffic registry to contrast it with tax returns filed by taxpayers.

The stated objective is to identify taxpayers who conceal assets or income through cross-analysis of patrimonial data. Vehicles are a relevant patrimonial indicator: their ownership, value and number can reveal undeclared economic capacity.

The amendment does not create a new agreement from scratch, but rather updates the legal framework of the existing agreement so that it is fully compatible with current regulations on data protection and electronic administration.

Economic and operational impact

The direct impact is not a new cost or additional fee. The impact is one of increased tax risk: the probability that the Tax Authority will detect inconsistencies in vehicle declarations is now significantly higher.

The main operational consequences for companies and self-employed workers are:

• Greater exposure to information requests if vehicle ownership does not match what is declared in personal income tax, corporate income tax or VAT.
• Risk of tax regularization if vehicles used in economic activity are not properly declared or their use is not documented.
• Possible start of inspection procedures resulting from automatic data cross-checking, without the need for prior complaint or in-person visit.

For companies with vehicle fleets, consistency between the Traffic registry and accounting and tax returns becomes a priority control point. For self-employed workers who deduct vehicle expenses, ownership and declared use are now more exposed to automatic cross-checking.

Who does it affect?

• Self-employed workers who have vehicles used in their business activities and deduct depreciation, fuel or maintenance expenses in their personal income tax or VAT return.
• Companies and SMEs with vehicle fleets whose ownership is registered in the Traffic registry and must match the assets declared in Corporate Income Tax.
• Managers and partners who use company vehicles as compensation in kind and whose declaration must correctly reflect that situation.
• Any taxpayer natural or legal person who owns motor vehicles whose apparent patrimonial capacity does not match declared income or assets.
• Tax advisors and management firms who manage the tax affairs of clients with vehicles, as they will need to review consistency between ownership and declarations.

Practical example

A self-employed worker under the direct estimation regime declares a single vehicle used in their business at 50% and deducts the corresponding expenses. However, the Traffic registry shows them as owner of three additional vehicles in their personal name.

With the new strengthened agreement between the AEAT and Traffic, the Tax Authority can automatically cross that information and detect that the taxpayer owns four vehicles in total, but has only declared one. This can generate an information request to justify the situation of the undeclared vehicles: if they are for private use, if they generate undeclared income (rental, for example), or if there is a patrimonial inconsistency.

The same scenario applies to a company that has vehicles registered in its name in Traffic but that do not appear as assets in its accounting or whose depreciation has not been properly declared in Corporate Income Tax.

What should companies do now?

1. Audit the ownership of all vehicles registered in the name of the company or self-employed worker in Traffic and verify that they match the assets declared in Corporate Income Tax or personal income tax.
2. Review VAT deductions and vehicle expenses in recent returns to ensure they are properly justified and documented, especially in the case of mixed-use vehicles.
3. Check consistency between the Traffic registry and accounting: vehicles that appear in Traffic must be reflected as assets or their absence justified (vehicles sold, transferred, deregistered).
4. Document the use of company vehicles by partners or managers and verify that the corresponding compensation in kind is properly declared.
5. Consult with your tax advisor if there are vehicles whose situation could generate inconsistencies in an automatic data cross-check, and regularize before receiving a request.

Official source

Disclaimer: This article is for informational purposes only and does not constitute legal or tax advice. The information provided is based on the official publication in the BOE (Official State Gazette) and current regulations as of the publication date. Tax regulations are subject to change and interpretation by the competent authorities. We recommend consulting with a qualified tax advisor or legal professional before taking any action based on this information. The author and publisher assume no responsibility for the accuracy, completeness or timeliness of the information provided, nor for any damages or losses that may result from its use or misuse.