Performance by cohort
2 year bands · 4,167 tests
Pass rate climbs 1.4 points across the cohorts — newer Boxer 435 Pro L4h2 Bluehdi examples clear the test more reliably than the early cars.
Pass
72.9%
Fail
20.7%
PRS
5.5%
Avg mileage at test
75,818 mi
Pass
74.3%
Fail
17.5%
PRS
6.8%
Avg mileage at test
56,560 mi
Cohort = vehicle's first-registration year band. Same model, different generations of build.