New analysis of nearly 50 million MOT tests challenges the traditional assumption that high mileage automatically means mechanical unreliability
An analysis of 47.4 million MOT tests has revealed that the conventional wisdom about avoiding high-mileage used cars may no longer apply to electric vehicles. The research, commissioned by the British Vehicle Rental and Leasing Association, found that electric cars become significantly more reliable than petrol equivalents as mileage climbs.
The study, conducted by independent transport research organisation New AutoMotive, examined official DVSA records to track how electric and petrol cars perform as they age and accumulate miles. The findings paint a striking picture: while both vehicle types show similar failure rates at lower mileages, electric cars diverge sharply from petrol vehicles once they exceed around 60,000 miles.
Dramatic Reliability Gap at High Mileage
At lower mileages, the differences are minimal. Between 20,000 and 40,000 miles, 12.0% of electric vehicles failed their MOT compared with 11.7% of petrol cars. However, this changes dramatically as cars accumulate more distance.
From 60,000 miles onward, electric car failure rates level off at approximately 16%, while petrol and diesel cars continue deteriorating. Among vehicles aged three to eight years with 90,000 to 120,000 miles, 16.5% of electric cars failed their MOT compared with 22.1% of petrol cars—making electric vehicles around 25% less likely to fail. Above 120,000 miles, the gap widens further, with 16.0% of EVs failing versus 23.5% of petrol vehicles.
The findings suggest that the mechanical simplicity of electric drivetrains becomes increasingly advantageous as vehicles age. Unlike traditional engines with hundreds of moving parts, electric motors have significantly fewer components prone to wear and failure.
Older EVs Staying on the Road Longer
The research also revealed that older electric cars are remaining in use longer than their petrol counterparts. When tracking whether vehicles returned for MOT within 30 months, 94.6% of 15-year-old electric cars returned compared with 88.1% of petrol cars. This suggests electric vehicles are not being scrapped or exported earlier than petrol models—contrary to what some might expect.
Interestingly, this longevity is not attributable to electric cars becoming low-mileage vehicles in their later years. Electric vehicles actually recorded higher median annual mileage than petrol cars at every age examined between four and 16 years, indicating they are being actively used rather than retired to occasional driving.
Areas Where EVs Still Fall Short
The study did identify some areas where electric cars underperform. EVs recorded approximately 1.8 times as many tyre defects as petrol cars, though researchers noted this problem was more pronounced in earlier electric vehicles adapted from petrol engine platforms.
Contrary to expectations about heavier batteries, electric cars actually showed fewer suspension defects than petrol vehicles between 60,000 and 90,000 miles. Regenerative braking also produced mixed results, with high-mileage EVs experiencing fewer brake defects overall, though older, low-mileage electric cars showed increased friction-brake corrosion.
Hybrid vehicles performed surprisingly well in the analysis, recording lower MOT failure rates than both petrol cars and battery-electric vehicles in several categories.
The Battery Question Remains
One crucial limitation of the research is that MOT tests do not measure battery health or remaining capacity. While the roadworthiness assessments examine brakes, tyres, suspension, steering and lights, they cannot determine electrochemical degradation or charging performance. Researchers emphasise that battery health should be considered separately when evaluating a used electric vehicle.
Despite this limitation, the data challenges long-held assumptions about mileage as an automatic indicator of vehicle decline. A well-maintained, higher-mileage electric car can offer durability comparable to or better than lower-mileage petrol vehicles, potentially opening the second-hand EV market to millions more affordable buyers during the transition to electric transportation.
