Can You Drive With a Cracked Windscreen?

While the rules here aren’t hard and fast, if a crack is deemed as obscuring your view of the road then you could be charged with a fixed penalty and three points on your licence.

Getting a crack in your windscreen is a great way to ruin a day at the best of times, but it’s liable to make the day even worse if you’re not able to drive as a result. From chips to cracks, what are the legalities, and at what point do you need to make sure your windscreen is looked at, repaired, or replaced? Let’s find out.

Why is a cracked windscreen a problem?

We should begin by pointing out that cracks in modern windscreens aren’t so much a danger to you in the way that you might think. They’re not going to shatter into a billion pieces of glass (usually) because modern screens are laminated with transparent plastic layers precisely to stop this happening.

The plastic layers mean that the windscreen behaves like a flexible layer of sorts – something might pierce it, but impacts are most usually going to cause it to crumple rather than shatter.

The real problem, then, is visibility.

A cracked windscreen might not be a problem for shattering, but when the glass cracks, it can quickly crack to the extent that it severely limits visibility – either through tiny cracks making the windscreen no longer transparent or through the cracks distorting the view. This, in turn, can make it very difficult to accurate gauge distance and space – if you can see through that part at all.

How do windscreen cracks happen?

Other than from a serious impact, almost all cracks start as chips, caused by stones kicked up from the road – or even from things dropped by birds. Annoyingly, this is something that you rarely have control over – another one of the cruel elements of fate like potholes and family dinners.

A stone or piece of road debris usually chips the windscreen, and accumulated jolts from road surfaces eventually work the chip into a crack.

Sometimes, this can happen surprisingly suddenly – the glass will look fine one moment, and the slightest jolt becomes the straw that breaks the camel’s back.

What can I do about a chipped windscreen?

It’s usually best to have a windscreen repaired while the chip is still small – a stitch in time saves nine, after all. This is primarily because of two reasons:

1. The way that windscreen damage is repaired
2. The fact that cracks create new faces within the structure of the glass

To address the first issue, a chip is usually repaired by firstly grinding it smooth, then injecting a type of transparent epoxy filler to fill it seamlessly and re-strengthen the piece of glass. This works because the epoxy can easily fill the small pit left in the glass after grinding and, in fact, can be done without grinding the glass at all – but failing to do so usually results in the chip still being visible after repair.

But when it comes to a crack, it’s often very difficult for the epoxy to be poured between the cracks because they’re usually incredibly thin. But even a thin crack over a large distance can wreak havoc for distorting how you see through it. Because a new face is essentially created for every crack, there’s now another surface that can reflect or refract light. Over a complex crack, you quickly find yourself looking into a kaleidoscope!

And if a police officer sees you driving with that kaleidoscope, you could be in big trouble.

What’s more, repairing a chip is usually much cheaper – as a complex crack will often simply need the entire windscreen to be replaced.

Don’t sit on chips!

While we don’t offer windscreen replacements and repairs, the case is the same for any part of your car that needs attention. Replacing a worn brake pad in time, for example, can save you having to replace the entire brake disc – so don’t sit on the chips, get them fixed! Trust the experts at your local Kwik Fit Centre.