Checking your tread depth of your car tyres is important, as you will need to know when the tyres are worn out. If you don’t know the tread depth you might be driving with worn out tyres. It is illegal to drive with worn out tyres and the decline in key safety properties start once you go below 4 mm. It is even more critical for your winter tyres than it is for your summer tyres. You can check it with indicators built into the tread, which is called Driving Safety Indicator, which displays a number on the tread as the tread is worn down. You can also visit a SnapSkan site, where your tyres will be scanned and you will get the results digitally. You can also measure it with a tread depth gauge or a coin to monitor the depth.