An editorial overview, not legal advice. The duty to report and the test follow Art. 34 VTS and the practice of your road traffic office. As of August 2026.
Report it before you drive
Art. 34 VTS: altered vehicles must be retested before they are used again. The keeper is responsible for the report. "It has been like that for ages" is not an entry.
What typically falls under the extraordinary test:
- Engine, mixture formation, exhaust system (including a catalytic converter removed)
- Chassis, wheels, tyres outside the dimensions on the papers
- Brakes
- Lighting (colour, type, number)
- Seats and belts, body structures
- A changed top speed or power output
The exact list is in Art. 34 VTS. If in doubt, ask the road traffic office before the modification, not after.
Veterans and modifications
Since the ASTRA directive of 10 July 2026 (in force since 1 August 2026), veteran status no longer requires proof of the « original specification ». What counts is a technically sound condition. That does not release you from Art. 34 VTS: changed technology must be reported and entered, or the car fails the MFK and often the veteran assessment as well.
Originality still matters for value and for collectors' interest. See Originality. It is no longer a condition of the directive in its own right for Code 180.
Hence the order:
- Clarify whether the planned work must be reported, and how it affects market value.
- Have the modification carried out properly, with an invoice and photographs.
- Report the change and present the car.
- Only then a veteran assessment, or a sale as a veteran.
Frequent cases on classics
- Catalytic converter removed: in Switzerland an MFK problem, especially on cars homologated or later fitted with a converter. Compare the emissions papers and the vehicle registration certificate.
- Chassis lowered, different springs, different dampers: without proof and an entry, a defect that keeps coming back.
- US lighting: red rear indicators and sealed-beam headlamps are treated with a strictness that varies by canton. Orange indicators and approved units spare you the argument. See Import.
- Wheels: size and load capacity must match the Typenschein or a certificate.
- Frame replacement (e.g. 2CV): invoice, origin and entry belong together. A cheap replica without an entry is a risk at the test.
Who helps
A workshop focused on the MFK and veteran inspection knows what the local test centre expects. The examiner on the ramp is not the right place for the first question of principle.
After the entry, update the papers and, if the car is insured, the insured value. A modification without an adjusted policy is a second job to sort out if there is a claim.
Sources
- VTS Art. 34 (duty of extraordinary testing)
- ASTRA directives for veteran vehicles (original specification)
- Cantonal notes on altered vehicles