However well a vehicle damaged in a traffic accident is repaired, it sells for less on the second-hand market than comparable undamaged vehicles. This difference is called diminished value and can be claimed from the compulsory traffic insurance of the party at fault.
Basic principle: actual loss
Diminished value is the difference between the vehicle's undamaged second-hand market value immediately before the accident and its market value after repair. By its decision of 17.07.2020, E.2019/40, K.2020/40, the Constitutional Court annulled the provision limiting the loss to the General Conditions. Since that decision, diminished value has been determined in court and arbitration practice according to the principle of actual loss, within the framework of the tort provisions of the Turkish Code of Obligations and the Highway Traffic Law. The view that the formula annexed to the General Conditions cannot be applied directly has also been adopted in decisions of the Insurance Arbitration Commission's Objection Panel.
Main criteria taken into account
1. Market value of the vehicle. The starting point is the market value, on the accident date, of an undamaged vehicle of the same make, model, year and equipment. The casco value list published by the Insurance Association of Türkiye and averages of second-hand listings are often used to determine this value.
2. Nature of the damage and damaged parts. A part that has only been repainted does not have the same effect as a part that has been replaced. Damage to structural parts such as pillars, chassis or wheel arches causes the greatest drop in value in the eyes of buyers.
3. Age of the vehicle. Diminished value is proportionally higher for new and lightly used vehicles, because buyers pay a noticeable premium for an undamaged vehicle.
4. Mileage. Diminished value is more pronounced for low-mileage vehicles. As mileage increases, the effect of the same damage on market value decreases.
5. Previous damage records. If the vehicle has recorded damage from earlier accidents, particularly to the same part, the effect of the new accident on diminished value may be assessed differently. Previous damage does not by itself eliminate diminished value; it is examined separately in each case.
6. Fault ratio. If the driver of the damaged vehicle was also at fault, compensation is reduced in proportion to that fault. A driver who is fully at fault cannot claim diminished value from the other party.
How is the exact amount determined?
In a claim made to the insurer, diminished value is assessed by a loss adjuster. In the event of a dispute, the Insurance Arbitration Commission or the court determines the actual loss through an expert examination. Online calculation tools only give an approximate idea and are not binding.
You can use the free Kaza Dosyam tool to keep your accident information in an organised file: kazadosyam.katarhukuk.com
This article is for general information only and does not constitute legal advice. Each specific case must be assessed in its own circumstances. Updated: 10 October 2026
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