2017 sees two more checks added to the CT. Both are a bit of a bother!
The first concerns the engine management light. If it is illuminated at the time of the test it will fail. Some cars may have a minor fault, maybe just a faulty sensor, which would not actually affect the proper running of the car but could be difficult & expensive to find. My own car is a case in point! I bought it with the light lit & it has passed 2 CTs & covered 80,000 kms since. Until I find the reason it will not pass another.
More of a concern is the second rule. Front window glass must allow 70% of light through. Most modern cars in standard form meet that requirement but many owners opt to add a heavier tinted film which restricts the light & heat inside the car in summer. The new law has been introduced because reduced visibility could cause accidents but it is more to do with being able to see who/what is going on inside the car - seat belts, mobile phone use & weapons - as sensible tints should not make that much difference.
Now here’s the problem. Although the 30% maximum light blockage limit is specific, as is the punishment regime for infringement, the test is purely subjective! Neither the gendarmes nor the CT station have any kind of measuring device so if in the opinion of whoever is checking is that your windows are too dark then you will suffer. It is a bit like being convicted of murder because you look like one!
I have invested in a machine from the USA for testing tints as used by most law enforcement agencies around the world.
My car has extra tints & I asked my local CT station if it would pass. The man responsible checked & proclaimed my windows to be ok, although he was not sure if the gendarmes would agree. According to my machine my windows block 82% of the light/allow 18% through. Different from the 30%/70% by quite a margin! Still, let the gendarmes prove it without a meter!