Illegal Tyre Index Report

Where in the UK has the Most Accidents, MOT Failures & Fines Caused by Illegal or Defective Tyres?

Faulty car tyres are a serious road safety hazard that can cause vehicle problems such as longer braking distances, loss of control, and even catastrophic blowouts. Whether the problem stems from wear and tear, manufacturing defects, poor maintenance, or incorrect tyre fitting, the consequences can be life-threatening for drivers, passengers, and other road users.

Driving with faulty tyres can result in fines of up to £2,500 and three penalty points per tyre. More importantly, unsafe tyres significantly increase the risk of accidents, particularly in poor weather or high speeds.

But where in the UK is the issue the worst, where people are having the most accidents and failing MOTs due to their tyres?

The areas with the most accidents caused by tyres

We’ve analysed data from the Department for Transport to determine which parts of the UK have had the most collisions caused by illegal, defective, and under-inflated tyres between 2019 and 2023, calculating this per 100,000 people in each area.
 

Smaller and more rural areas dominate the top end of the list, especially those in the South West. 

• Wiltshire had the highest rate, with 46 collisions between 2019 and 2023, equating to 8.88 incidents per 100,000 people.
• Cornwall followed closely with 44 collisions and a rate of 7.61 per 100,000.
• Herefordshire recorded only 14 incidents overall but ranked third due to its smaller population, giving it a rate of 7.37 per 100,000.
• Dumfries and Galloway comes in fourth and is the Scottish area with the highest collision rate (6.86 per 100,000 people).
• Devon ranks fifth and is the most populated area in the top ten. Its accident rate is 6.72 per 100,000 people.

Rural areas, especially in the South West and parts of Wales, experience more tyre-related collisions per capita.

Cities and other urban areas have much lower rates, which may be due to people travelling shorter distances, having better access to maintenance, or relying less on cars.
 

Where have accidents caused by tyres increased the most?

We’ve also looked at the areas with the most significant increase in collisions due to illegal, defective, and under-inflated tyres between 2019 and 2023. However, the actual number of incidents remained low across most regions.

• Bristol recorded a 400% rise, from just one incident in 2019 to five in 2023.
• Carmarthenshire saw a 300% increase (one to four incidents), while Cambridgeshire rose by 250%, from two to seven incidents.
• More than 30 local authorities — including Medway, Newport, Barnet, and Glasgow City — reduced their tyre-related collision count to zero in 2023.
• There were also notable decreases in Nottinghamshire (-85%) and Suffolk (-86%).
• Although these figures involve small absolute numbers, the trend may reflect growing risks tied to tyre neglect in certain areas.

The most common causes of vehicle collisions

Next, we wanted to compare defective tyres to other vehicle defects that cause vehicle collisions, again looking at the years between 2019 and 2023. Over these five years, 6,762 collisions were attributed to vehicle defects.

• Faulty brakes were the leading factor by a significant margin, cited in 2,668 collisions, equating to almost two-fifths (39%) of all such incidents. This underscores the critical role of brake maintenance in road safety.
• Illegal, defective, or under-inflated tyres were the second most common issue, causing 1,856 collisions, more than a quarter (27%) of the total. This highlights the importance of regular tyre checks and proper inflation to prevent accidents.
• In third place, defective steering or suspension was reported in 984 cases (15%), followed by faulty lights or indicators at 689 incidents (10%). These can impact visibility and communication with other drivers, especially in low-light conditions.

The areas with the most vehicle collisions caused by defective tyres

Illegal, defective, or under-inflated tyres were the leading vehicle defect in one in three local authorities nationwide. Looking more closely, some local authorities saw tyre defects responsible for most or all vehicle defect collisions.

• East Ayrshire stands out with a 100% rate, where all four recorded vehicle defect collisions involved faulty tyres, followed by Bridgend and Thurrock, with rates of 71% and 69%.    
• Welsh and Scottish areas are also featured at the top of the list. Merthyr Tydfil, Midlothian, North Ayrshire, Argyll and Bute, Dumfries and Galloway, and Newport all recorded tyre issues in over half of vehicle defect collisions.
• Conversely, areas in major cities ranked among the lowest. Ten areas, including the City of London and Sefton, recorded zero tyre-related collisions.

Tyre-related collisions by road type

Collisions caused by faulty tyres were most common on A roads, which accounted for 802 collisions, or 43% of the total. This makes them the most hazardous road type for tyre-related defects, likely due to higher speeds and frequent use.

‘Other roads’ — including minor or unclassified roads — ranked second, with 628 collisions (34%). This shows that while these roads may carry less traffic, tyre-related incidents remain a concern.

B roads recorded 231 collisions (12%), while motorways, despite being associated with higher speeds, saw the fewest tyre-related collisions at 195 (11%). This may be due to better road quality or more regular maintenance.

How many MOTs fail due to tyre defects

We’ve also looked at MOT test data to see what defects are most likely to cause a car to fail, and how tyres rank.

• Lamps, reflectors, and electrical equipment top the list, with 11.19% of vehicles tested showing defects in this category, making up a quarter (25.11%) of all recorded defects. While these faults are common, they are rarely dangerous, accounting for just 0.15% of all tests and 1.35% of all hazardous defects.
• In contrast, although only the fourth most common defect type at 6.37% of tests, tyres are by far the most likely to be dangerous. They represent 4.83% of all tests with dangerous defects - almost 60% of all hazardous defects fall under this category, underlining the safety risk posed by tyre issues.
• Brakes come third (6.83% of tests) but contribute highly to dangerous defects (29.12%), making them the second most hazardous category after tyres.
• Suspension issues are also common, affecting 9.02% of vehicles. They are responsible for over 19% of all defects, though the share of dangerous defects (5.34%) is lower than that of tyres and brakes.
• At the lower end, seatbelts, speedometers, and vehicle identification account for less than 0.5% of defects, and virtually none are classified as dangerous.

Nyo Logan, a Blackcircles.com tyre expert, explains why it’s essential to check your tyres before driving and how to check a vehicle's tyres:

“Tyres are the only part of your vehicle that make contact with the road, so their condition has a significant impact on your safety. Worn, damaged, or underinflated tyres can increase braking distances, reduce grip, and raise the risk of blowouts - especially in poor weather. 

“Illegal, defective, or underinflated tyres contribute to hundreds of UK road collisions yearly. They can also result in fines of up to £2,500 and three penalty points per tyre if found to be below legal standards. Here’s what to check:

• Tyre pressure

• Tread depth

• Tyre condition

• Even wear

• Spare tyre

“Regular tyre checks take only a few minutes but can save lives. It’s a simple habit that helps prevent accidents, protects your wallet, and keeps you on the right side of the law.”

Methodology

Data on the number of collisions due to tyres that are illegal, defective, or under-inflated over the last five years and the most dangerous vehicle defects by number of collisions were sourced from the Department for Transport’s road safety statistics: data tables ( RAS0701: Collisions, casualties and road user type).

Data on the number of collisions due to illegal, defective, or underinflated tyres by road type were also taken from the same source.

Data on the proportion of MOTs that fail due to tyre defects and the percentage of these defects listed as dangerous was sourced from the Driver and Vehicle Standards Agency’s MOT testing data for Great Britain.