Even if your vehicle is repaired after a traffic accident, it cannot retain its former value in the second-hand market due to recorded damage. This decrease in price is legally called “vehicle diminution in value” and is a real item of damage that can be claimed from the at-fault party’s insurance or directly from the driver. So, exactly how is this compensation calculated, who can claim it, and which errors lead to a loss of rights? Below you will find all the details in light of current legislation and judicial decisions.
1. Legal Grounds:
Article 90 of Highway Traffic Law (KTK) No. 2918: It determines the basic criteria for calculating compensations. Following the amendment by Law No. 7327 and Constitutional Court annulment decisions, the criteria of “market value, level of usage, damaged parts, and damage amount” are taken as a basis in the calculation.
Article 92 of the Highway Traffic Law No. 2918: Regulates cases outside the scope of Mandatory Financial Liability Insurance (ZMSS). (E.g.: Diminution in value cannot be claimed for scrapped vehicles).
Articles 49 and 54 of the Turkish Code of Obligations (TBK) No. 6098: Regulates the principle of full compensation for the decrease in assets (actual damage) resulting from a tortious act.
2. Calculation Method (Difference Criterion):
Pre-Accident Value: The fair market value determined by taking into account the vehicle’s brand, model, mileage, and undamaged condition at the time of the accident.
Post-Accident Value: The fair market value of the repaired vehicle, reflecting the negative impact of the accident and repair on the market (from the perspective of a second-hand buyer).
Compensation Amount: (Pre-Accident Market Value) – (Post-Accident Market Value) = Diminution in Value.
3. Points to Consider:
Statute of Limitations: Pursuant to Article 109 of the Highway Traffic Law, it is 2 years from the date the damage and the liable party for compensation are learned, and in any case, 10 years from the date of the accident.
Fault Rate: The amount of compensation is distributed according to the fault rates of the parties in the accident.
Precedent Decision: The decision of Konya 2nd Civil Court of Commerce dated 13.04.2023, numbered 2022/402 E. and 2023/260 K., is a current practice confirming that the calculation should be based on the difference between market values, not the formulas in the general conditions.
1. Legal Basis and Regulatory Framework
Vehicle diminution in value compensation is “actual damage” compensation aimed at remedying the decrease in the assets of the injured party as a result of a tortious act. The legal bases for this type of compensation are as follows:
Highway Traffic Law No. 2918 (HTL) Art. 90: Defines the basic criteria for calculating compensation. Following the amendment of Law No. 7327 and the annulment decisions of the Constitutional Court (AYM), the criteria of “market value, level of previous use, damaged parts, and amount of damage” are taken as basis in the calculation.
HTL No. 2918 Art. 92: Regulates cases outside the scope of Compulsory Financial Liability Insurance (CFLI); for example, diminution in value cannot be claimed for vehicles written off as scrap.
Turkish Code of Obligations (TCO) No. 6098, Arts. 49 and 54: Regulates the principle of full compensation for the decrease in assets resulting from a tortious act (the principle of actual damage).
2. Key Criteria for Determining Diminution in Value Compensation
According to court decisions and established Supreme Court precedents, when calculating vehicle diminution in value, a single piece of data is not relied upon; rather, the vehicle’s technical and economic condition is evaluated as a whole. As emphasized in the decision dated 08.10.2025, with file no. 2024/610 E. and decision no. 2025/708 K., of the Istanbul 1st Commercial Court of First Instance, diminution in value depends on the following factors:
Vehicle Identification Information: Make, model, model year, and purpose of use.
Usage Status: Vehicle’s mileage, age, and level of previous use.
Nature of Damage: The severity of the damage, the characteristics of the damaged areas (parts affecting static stability such as chassis, pillars, main load-bearing components), painted parts, and the amount of damage.
Repair Quality: Whether replaced parts are original, the technological methods applied in repair, and qualified workmanship (e.g., use of authorized service).
Past Records: Whether the vehicle has been involved in an accident before and its past damage records (Tramer information).
3. Calculation Method: “Difference Criterion”
In current judicial practice, the “Difference Criterion” method has been adopted instead of the restrictive formulas in the general conditions of insurance. This method was taken as a basis for determining “actual and direct damage” in the decision of the Istanbul 2nd Commercial Court of First Instance, dated 29.12.2021, numbered 2019/475 E. and 2021/967 K.
Calculation Formula: (Fair Market Value Before Accident) – (Fair Market Value After Repair) = Diminution in Value Compensation
The precedent decision of the Konya 2nd Commercial Court of First Instance, dated 13.04.2023, numbered 2022/402 E. and 2023/260 K., is a current practice confirming that the calculation should be based on the difference between market values, not on the formulas in the general conditions. Similarly, in the decision of the Konya Regional Court of Justice, 3rd Civil Chamber, dated 07.05.2024, numbered 2024/711 E. and 2024/837 K., it was stated that real market conditions should be taken into account and that restrictive regulations cannot be applied in line with the Constitutional Court’s annulment decisions.
4. Emphasis on Market Value in Court Decisions
Courts mandate market research by experts in determining diminished value. In the decision of the Konya 1st Civil Court of Commerce dated 08.05.2025, with file number 2024/958 E. and decision number 2025/309 K., the results reached by the expert after conducting the necessary market research were given credence.
In the decision of the Ankara Regional Court of Justice 26th Civil Chamber dated 09.11.2023, with file number 2021/1175 E. and decision number 2023/840 K., it was emphasized that calculations made solely according to the notification in the General Conditions of Insurance are contrary to Supreme Court practices and would be considered an incomplete examination. To determine the actual damage, comparable sales must be investigated, and the second-hand value of the vehicle in its repaired state must be determined with concrete data.
5. Procedural Matters to Consider
Statute of Limitations: Pursuant to Article 109 of the Road Traffic Law (KTK), claims for diminished value compensation must be filed within 2 years from the date the damage and the liable party are learned, and in any case, within 10 years from the date of the accident.
Fault Ratio: The amount of compensation is distributed according to the fault ratios of the parties in the accident. As stated in the decision of the Kayseri 2nd Civil Court of Commerce dated 22.05.2024, with file number 2023/82 E. and decision number 2024/501 K., the final compensation amount is determined by multiplying the calculated total diminished value by the fault ratios.
Proof: In diminished value claims, the damage file, appraisal report, vehicle photographs, and service records are considered means of proof (Izmir 1st Civil Court of Commerce, 17.06.2025, 2024/48 E., 2025/492 K.).
Conclusion
Vehicle diminished value compensation is calculated based on technical criteria such as the vehicle’s make, model, mileage, and the nature of the damaged parts, as well as the difference between its fair market values before and after the accident. Judicial authorities, in light of the Constitutional Court’s annulment decisions and the current regulations in Article 90 of the Highway Traffic Law (KTK), apply the principle of “actual damage” based on the specifics of the concrete case and market realities, instead of the mathematical formulas in the general insurance terms.
Why is Expert Legal Support Necessary?
Although the vehicle diminished value process may seem simple at first glance, in practice, it can lead to significant loss of rights due to insurance companies’ low offers, incomplete expert reports, and procedural errors. Calculations made by insurance companies using restrictive formulas in general terms often fall far below the actual damage; in cases filed without expert support, there is a risk of insufficient claims, incorrect adversarial parties, or statute of limitations.
As 2M Hukuk Law Office, we provide end-to-end legal support to our clients in claims for diminished value, difference in damage, deprivation (replacement vehicle), and total loss compensation arising from traffic accidents, primarily in Istanbul (Anatolian Side), and also in the Tuzla, Pendik, Kartal, Maltepe, and Gebze (Kocaeli) regions. At every stage of the process:
We conduct a technical review of the Tramer (traffic insurance record) and damage file, introducing the correct precedents and market value to the file to reveal the true loss.
Against expert reports, we prepare effective objection petitions in line with the “Difference Criterion” and the current Constitutional Court/Supreme Court approach.
By managing the processes of the insurance arbitration commission and commercial courts, we prevent errors related to statute of limitations and hostility.
If you wish to receive expert legal support for your vehicle’s depreciation after a traffic accident in the Istanbul Anatolian Side and Kocaeli region, you can contact 2M Hukuk Law Office to have your file undergo a free preliminary assessment.
Frequently Asked Questions (FAQ)
Who can claim vehicle depreciation compensation?
The vehicle owner who is not at fault or is less at fault in the accident can claim the depreciation of their vehicle. The claim can be directed to the compulsory traffic insurance (ZMSS) insurer of the at-fault party and/or the at-fault driver/operator.
What is the statute of limitations for a depreciation claim?
Pursuant to Article 109 of the Highway Traffic Law (KTK), a statute of limitations of 2 years from the date the damage and the responsible party are learned, and in any case, 10 years from the date of the accident, applies. Missing this deadline results in loss of rights.
My vehicle sustained minor damage, can I still claim diminished value?
The nature of the damage is decisive. While diminished value may not arise from cosmetic damage like small scratches/paint, compensation becomes relevant as damage to chassis, pillars, structural parts, and painted parts decreases market value. Each case should be evaluated with concrete data.
Am I obliged to accept the amount offered by the insurance company?
No. Insurance companies often offer low amounts using restrictive formulas in their general terms. Actual damage is calculated based on market rates using the “Difference Criterion”; arbitration or legal action can be pursued against a low offer.
Can diminished value be claimed for a scrapped or total loss vehicle?
No. According to Article 92 of the KTK (Highway Traffic Law), diminished value cannot be claimed for scrapped/total loss vehicles. In this case, the relevant items are the total loss (full damage) value of the vehicle and other related damages.
Which documents are required for a diminished value claim file?
The accident report, damage file, appraisal/repair invoices, vehicle registration, Tramer records, vehicle photos, and service records (if any) are the basic evidentiary documents.
