The glass in our cars serves a number of purposes to further the safety and comfort of the occupants. The most obvious is the taking and giving of information. Windows allow us to take in information such as signals from other road users. And they allow those other road users to observe us and make deductions about our intentions.

Over time the windows of an ordinary passenger vehicle have become bigger to allow the taking and giving of information. Sometimes we forget the importance of our windows and don’t keep them as clean as we should.

The window is also part of the structural integrity of the vehicle. Without the glass in the window, it would be almost impossible to drive your vehicle at speed. The process of driving would become very uncomfortable due to dust, insects and wind.

Along with the pillars and roof, the glass provides protection to the car’s occupants should the vehicle end up on the roof. The overall size and shape of the glass is an important aspect of the styling of a vehicle.

Throughout time, the glass used for windscreens has changed from ordinary to toughened, to safety laminate. This change was mainly to protect the occupants of the passenger compartment from harm.

For example, if a stone was to be spun from the back wheel of the vehicle in front on to your vehicle windscreen, its speed of impact will be that of your vehicle plus that of the stone. On a modern vehicle a windscreen should stay intact.

But did you know? Your side and rear windscreens are specifically made of toughened glass so that they shatter. This is so you are not trapped in your vehicle in the event of a bad crash.

Have you ever noticed that there is often a dot-matrix around the area behind the rearview mirror? This is there to soften the light when you look up to check your mirrors. The dot-matrix also extends around the edges of the windscreen to soften light which might otherwise be glare.

Then we have tinted windows. Tints are used for many reasons. Styling, privacy and heat reduction being the main ones. In sunny climates, tinting will protect the interior from damage. The main problem with tinted glass is the suppression of giving and receiving information and it’s not just about being able to see what the other driver is doing.

It’s about being able to gain information by looking through a vehicle’s glass. For example, when emerging from a junction with vehicles parked close to the mouth of that junction. We try to look through those vehicles.

Applied tints are sometimes sold on the fact that it is difficult for someone to break the window to which the tint has been applied. But think of it this way, it would also make it difficult for emergency services to break the window to rescue you. An applied tint could also invalidate your vehicles insurance as this could be viewed as a modification. You would need to check with your insurance company first, as after an accident the assessor will not be doing any favours. We’ve outlined some of the rules and penalties when it comes to tinted glass, just in case you were thinking about it!

The UK rules for tinted glass are:

  • Vehicles first used on 1 April 1985 or later, the front windscreen must let at least 75% of light through and the front side windows must let at least 70% of light through.
  • Vehicles first used before 1 April 1985, the front windscreen and front side windows must both let at least 70% of light through.

Penalties for having wrongly tinted windows:

  • a ‘prohibition notice’ stopping you using your vehicle on the road until you have the extra tint removed
  • a penalty notice or court summons

So before you go and tint those windows, make sure you know the rules, understand the penalties and have cleared it with your insurance company!