MOT Windscreen Fails: What You Need to Know

The annual Ministry of Transport (MOT) test is a crucial part of ensuring your vehicle is safe and roadworthy. While many drivers focus on brakes, lights, and tyres, the condition of your windscreen is also a significant factor. In fact, a surprising 8% of cars typically fail their MOT test specifically because of issues with their windscreens. This figure highlights the importance of regular checks and understanding the regulations surrounding this vital component. Since 1993, windscreen inspections have been a mandatory part of the MOT test, reflecting their critical role in driver visibility and structural integrity.

Understanding the MOT Windscreen Regulations

The DVSA (Driver and Vehicle Standards Agency) has set out clear guidelines for what constitutes a fail on a windscreen during an MOT. These rules are designed to ensure that your view of the road is not compromised, which could endanger yourself and other road users. The primary concern is the area swept by your windscreen wipers, as this is your primary field of vision. Any damage within this zone is more likely to lead to a fail.

Key Areas of Inspection

During an MOT, the examiner will pay close attention to several aspects of your windscreen:

• Chips and Cracks: The size, location, and type of chips or cracks are critical. Small chips, particularly those not directly in the driver's line of sight, might be permissible. However, larger chips or cracks, especially those extending towards the edges of the windscreen or into the driver's direct view, will likely result in a fail.
• The 'Zone A' Area: This is the most critical area, defined as the area directly in front of the driver, swept by the wipers. Any damage within this zone, even a chip larger than 10mm, or a crack longer than 10cm, will typically cause an MOT failure.
• The 'Zone P' Area: This is the passenger side of the windscreen, also swept by the wipers. Damage here, such as a crack longer than 40cm, can also lead to a fail.
• Adhesion: The windscreen must be securely bonded to the vehicle's body. If the bonding is compromised, leading to excessive movement or delamination, it can be a reason for failure.
• Tinting: While not always a direct MOT fail, windscreens must allow a minimum of 70% light transmission. Excessive tinting, whether from the factory or aftermarket, can lead to a fail.

Common Reasons for Windscreen Fails

The 8% failure rate on windscreens can be attributed to a variety of common issues:

The Impact of Damage Location

The specific location of damage is paramount. A chip the size of a 10p coin in Zone A, directly in your line of sight, is far more likely to cause a fail than a similar-sized chip on the very edge of the windscreen, outside the wiper sweep area. This is because the driver's primary field of vision is absolutely critical for safe driving. Even if a chip is small, if it's located in a position that distorts your view of the road or other traffic, it can be deemed a dangerous defect.

Repair vs. Replacement: When to Act

The good news is that many windscreen chips can be repaired, often without the need for a full replacement. Professional windscreen repair involves injecting a special resin into the damaged area, which bonds the glass and prevents the chip from spreading. This can often be done relatively quickly and cost-effectively.

When is Repair Possible?

• The chip is smaller than a 10p coin (approximately 20-30mm in diameter).
• The chip is not directly in the driver's line of sight (Zone A).
• The damage is not a crack extending towards the edge of the windscreen.
• The damage is not a long crack (over 10cm in Zone A, or 40cm in Zone P).

When is Replacement Necessary?

If your windscreen has a crack longer than the permitted limits, or if there are multiple chips or significant damage within the critical viewing areas, a full replacement is usually the only option to pass an MOT. It's always best to consult with a professional windscreen repair specialist to assess the damage and advise on the best course of action.

Maintaining Your Windscreen for MOT Success

Preventing an MOT failure due to windscreen damage is straightforward with a little proactive care:

• Regular Visual Checks: Make it a habit to inspect your windscreen for any new chips or cracks, especially after long journeys or driving on rough roads.
• Address Damage Promptly: Don't ignore small chips. Get them repaired as soon as possible before they spread or become more severe.
• Cleanliness: Ensure your windscreen is clean, both inside and out. Dirt and grime can obscure your vision and might make minor defects appear more significant to an MOT tester.
• Wiper Blade Condition: Check that your windscreen wipers are in good condition. Worn or damaged wipers can cause streaks and reduce visibility, which can also be a reason for failure.

Frequently Asked Questions (FAQs)

Q1: Can a small chip on my windscreen cause me to fail the MOT?

A: It depends on the location and size. A chip larger than 10mm in diameter within the driver's primary line of sight (Zone A) will typically cause a fail. Smaller chips outside this critical area may be acceptable.

Q2: How long can a crack be on my windscreen to pass the MOT?

A: In the driver's line of sight (Zone A), a crack longer than 10cm will cause a fail. In the passenger side swept area (Zone P), a crack longer than 40cm can also lead to a fail.

Q3: Is windscreen repair worth it?

A: Yes, if the damage is repairable, it's often significantly cheaper and quicker than a full windscreen replacement. It can also prevent a failed MOT.

Q4: What if my windscreen is tinted?

A: The windscreen must allow at least 70% of light to pass through. If the tint is too dark, either from the factory or aftermarket, it can result in an MOT fail.

Q5: Who is responsible for checking the windscreen during an MOT?

A: The MOT tester, who is a trained and authorised professional, is responsible for inspecting the windscreen according to the DVSA guidelines.

Conclusion: Prioritising Windscreen Health

With 8% of vehicles failing their MOT due to windscreen issues, it's clear that this is an area that drivers cannot afford to overlook. Understanding the regulations, particularly regarding chips and cracks in the critical swept areas, is essential. By conducting regular checks, addressing damage promptly, and seeking professional advice when needed, you can ensure your windscreen remains in a safe and legal condition, helping you to pass your MOT and, more importantly, to drive safely. Remember, a clear and undamaged windscreen is fundamental to your safety on the road. "Proud to keep your Vehicle safe" – and that includes your windscreen!