US-spec vs UK-spec: what actually matters
An American car was built to a different rulebook. The gap sits mostly in the lights.
How much of a car built for the US has to change before the UK will accept it? Less than you might expect. Steering stays on the left. Nearly all of the difference is lighting, and that is work we do in our own workshop before the car is tested.
Nearly all of it is lights.
Side by side
| Part | On the US car | What the UK test wants |
|---|---|---|
| Headlights | Different beam pattern, set up for traffic on the right | Dipped beam that dips to the left. Usually replaced or converted |
| Rear indicators | Often red, sharing the brake light | Amber on every indicator |
| Rear fog lamp | Not fitted | Required. Added and wired in |
| Side repeaters | Missing on many models | Checked on the IVA, expected on newer cars |
| Speedometer | Reads in miles per hour | IVA asks for miles per hour. Other UK rules on units may apply, so we check each car |
| Number plates | A different size | Usually fine on an unmodified car, if the plate is supported and lit |
| Glass and mirrors | Built to the US standard | Checked at IVA. Not on our usual conversion list |
Why the lights are the gap
US cars are built to US federal standards. UK approval is judged against UK ones. Where the two agree, nothing needs doing. Where they do not, the car has to be brought across, and the pattern is predictable. That is why we can usually say what a car needs from the make, model and year. Converting a US car goes through each change in turn.
Headlights
The DVSA's IVA manual says the dipped beam must dip to the left. US headlights are set up for driving on the right, so they usually need replacing or converting. Newer cars with LED or HID units come with extra requirements on levelling and cleaning, so those units are not a simple swap. For an older car going through the MOT, masks or converter kits on right-hand-dip headlamps are acceptable.
Indicators and side repeaters
Every indicator has to emit amber light. Plenty of American cars use red rear lamps that work as both brake lights and indicators, and those do not pass. Side repeaters, the small amber indicators on the wings or doors, are checked as well, and many US cars were never fitted with them.
Rear fog lamp
A rear fog lamp is required here and not fitted to US vehicles. It has to be red, work only with the dipped beam, main beam or front fog lamps, and not be switched by the brake control. It also needs an E or e approval mark. So it is a fitted and wired-in job, not a light stuck on the bumper.
What is not a problem
Steering. Left-hand drive does not change the approval route, and there is nothing on gov.uk that stops you registering one. The left-hand drive guide covers what it is like to live with.
Number plates. US plates are a different shape from UK ones, so the rear needs somewhere sensible to mount a UK plate. For an unmodified, mass-produced car, the IVA treats the plate space as met, and allows non-European cars to use the smaller space. What fails is a plate hanging off the car with nothing behind it, or a plate lamp that does not light it.
Glass. Glass, mirrors and the driver's forward vision are on the IVA list. It is not an item we usually convert, and an unmodified car with its original federal compliance label can be accepted on certain sections without being inspected on them. If anything on the car has been changed since it was built, tell us when you ask for a quote.
The IVA asks for a speedometer capable of showing miles per hour, which American dials do. Other UK rules on speedometer units may apply, so we check each car against the test it is actually taking.
Which differences matter depends on the car's age
Age decides the test, and the test decides the list. A car under ten years old takes an IVA and is measured against the full manual. A car ten years and older needs no approval, but does need an MOT, which is looser. The MOT's date rules are specific:
- Amber indicators
- Required on anything first used after 1 September 1965.
- Rear fog lamp
- Required on cars first used on or after 1 April 1980.
- Side repeaters
- Required on cars first used after 1 April 1986.
So a 1960s classic can need less than a 1990s pickup. Our IVA or MOT guide sets out which test your car takes.
What we do about it
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We read the car's age and build
The make, model and year tell us which test it takes and which lights are likely to need work.
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We look it over when it arrives
The list is based on the car in front of us, not a guess.
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We do the work in our workshop
Lighting is converted before the test. If we find anything beyond the usual, we talk to you first.
What it does to the quote
The conversion cost is in your original quote, not added later. It moves with the car: newer vehicles tend to cost more because integrated lighting units and bonded assemblies are harder to change than separate lamps. The costs page shows what goes into a quote, and the registration page covers what happens once the car has passed. Not sure what yours needs? Put the make, model and year in a quote request and we will list the changes it is likely to need.
Quick answers
Is a US-spec car unsafe on UK roads?
It is built to US federal standards. UK tests check the parts where the two sets of rules differ, mainly lights, and we put those right before the car is tested.
Do I need to fit a km/h speedometer?
It depends on the car. The IVA asks for a speedometer capable of showing miles per hour, and American dials show it. Other UK rules on speedometer units may apply, so we check each car and tell you at quote stage if anything else is needed.
Do I have to convert to right-hand drive?
No. Left-hand drive cars can be registered and driven in the UK. The changes are to the lighting, not the steering.
Does a classic need the same changes as a newer car?
Fewer, usually. The MOT only asks for a rear fog lamp on cars first used on or after 1 April 1980 and side repeaters on cars first used after 1 April 1986. Amber rear indicators are asked for on anything first used after 1 September 1965.
What does the lighting work cost?
It depends on the car, and it is in your original quote, so there is no surprise later. Newer cars with integrated lighting units tend to cost more than older ones with separate lamps.