UK MOT Data Shows EVs Outlast Petrol Cars at High Mileage

Skepticism about the long-term durability of electric vehicles has persisted for years, largely due to the relatively recent introduction of the technology. However, a new analysis of millions of annual roadworthiness tests in the United Kingdom suggests that this concern is unfounded. The data indicates that electric cars not only keep pace with petrol vehicles in their early years but ultimately surpass them in reliability as they accumulate higher mileages.

The study, reported by Electrek, utilized data from the standard MOT tests required for vehicles on British roads. These inspections focus on critical components such as suspension, brakes, tires, exhaust systems, and emissions. By tracking how often vehicles returned for subsequent tests, researchers could estimate the likelihood of a car falling out of service due to mechanical failure. This approach provides a real-world measure of durability that goes beyond theoretical design differences.

Reliability gap widens after 40,000 miles

In the initial phase of ownership, there is little statistical difference between the failure rates of electric and petrol vehicles. In fact, electric cars sometimes show slightly more issues early on, primarily because they tend to cover more miles annually. However, the trajectory changes significantly once vehicles exceed 40,000 miles. At this threshold, petrol cars begin to show higher rates of failure, and this divergence grows as mileage increases further.

By the time a petrol vehicle reaches 120,000 miles, it is 7.5% more likely to have failed than an equivalent electric vehicle. The study found that electric cars maintained a 16% failure rate compared to 23.5% for petrol models at this high mileage mark. This trend holds true regardless of the vehicle's age, suggesting that the fundamental mechanical design of electric cars offers a distinct advantage in long-term durability.

Design differences impact tire and brake wear

The analysis also highlighted specific areas where electric vehicles face different challenges. One notable trade-off is tire wear, which is consistently higher for electric cars. This is largely attributed to the added weight of the battery packs. Vehicles that were converted from petrol models to electric often suffer from higher tire wear because their chassis was not originally designed to support the extra mass. In contrast, purpose-built electric vehicles experience less severe wear, though it remains higher than in petrol counterparts.

Braking systems present another nuanced finding. While regenerative braking reduces the frequency of friction brake use, leading to fewer overall brake problems, older electric vehicles can develop specific issues. Cars over ten years old showed higher rates of brake failure, likely due to corrosion from underuse. Drivers are advised to engage friction brakes periodically to prevent this, even when relying heavily on regenerative braking for daily driving.

Battery health not included in test data

A significant limitation of this study is that it does not track battery health, as this metric is not part of the standard UK MOT test. Consequently, the reliability figures do not account for battery degradation or replacement costs. However, separate research on battery longevity suggests that most electric vehicle batteries retain about 90% of their capacity even after 90,000 miles of operation. This implies that while battery health is a separate concern, it may not undermine the mechanical durability advantages shown in the MOT data.

For consumers considering an electric vehicle, the data suggests that long-term mechanical reliability is a strong selling point. While specific components like tires require more attention, the overall likelihood of the vehicle remaining roadworthy is higher for electric models than for petrol ones, particularly in the high-mileage range. This evidence helps counter the narrative that electric cars are inherently less durable over the long term.