Mercedes A Class vs Vauxhall Astra
Take the Mercedes A Class for lower age-adjusted MOT risk: its index is 91.3 versus 109.1 for the Vauxhall Astra, and the 95% confidence intervals do not overlap.
Lower is better. The index adjusts for each fleet's exact age profile; the raw failure rate below does not. The index gap is 17.8 points. Data release dvsa-2024-v1.
Side-by-side evidence
| Measure | Mercedes A Class | Vauxhall Astra |
|---|---|---|
| Age-adjusted MOT Risk Index | 91.3 (90.8–91.8) | 109.1 (108.8–109.4) |
| Raw initial failure rate | 18.83% | 33.71% |
| Dangerous defects per 100 tests | 11.78 | 16.98 |
| Initial tests | 585,107 | 914,157 |
Where their MOT failures diverge
These are component groups present in both models' published top-six failure lists, sorted by the absolute gap. A positive difference means the Mercedes A Class records more failure items; a negative one means the Vauxhall Astra does.
| Component group | Mercedes A Class | Vauxhall Astra | Difference | Lower rate |
|---|---|---|---|---|
| Lamps, reflectors and electrical equipment | 8.8 | 29.9 | -21.1 pp | Mercedes A Class |
| Brakes | 8.0 | 20.9 | -12.9 pp | Mercedes A Class |
| Suspension | 12.7 | 24.1 | -11.4 pp | Mercedes A Class |
| Visibility | 11.1 | 13.1 | -2.0 pp | Mercedes A Class |
| Tyres | 11.0 | 13.0 | -2.0 pp | Mercedes A Class |
Counts are defect items, not the share of cars: one failed test can contain several items. A group absent from a model's top six is not treated as zero.
What the six-year test history says
The longitudinal layer follows the same vehicles between MOTs from 2019 to 2024. It separates a one-day retest from the harder question of what returns next year, and puts failures against miles actually driven.
| Component | Mercedes A Class | Vauxhall Astra | Difference | Tracked advisories |
|---|---|---|---|---|
| Steering | 2.9% | 10.0% | -7.1 pp | 6,297 / 54,668 |
| Suspension | 18.5% | 24.4% | -5.9 pp | 43,630 / 487,109 |
| Brakes | 9.8% | 15.4% | -5.6 pp | 204,031 / 855,827 |
| Lamps, reflectors and electrical equipment | 26.1% | 30.3% | -4.2 pp | 5,621 / 78,690 |
| Noise, emissions and leaks | 5.7% | 9.0% | -3.4 pp | 7,615 / 339,325 |
| Body, chassis, structure | 15.6% | 12.5% | +3.1 pp | 7,720 / 201,169 |
| Tyres | 8.8% | 10.8% | -2.1 pp | 281,478 / 923,540 |
| Identification of the vehicle | 2.9% | 4.0% | -1.1 pp | 16,187 / 114,542 |
| Seat belts and supplementary restraint systems | 4.3% | 3.4% | +0.8 pp | 4,240 / 17,849 |
| Visibility | 9.5% | 10.2% | -0.8 pp | 1,246 / 3,735 |
| Measure | Mercedes A Class | Vauxhall Astra |
|---|---|---|
| Repaired and passed the same day | 48.3% | 46.0% |
| Passed 1–10 days later | 49.3% | 51.4% |
| Median retest delay | 1.0 days | 1.0 days |
| Failures per 10,000 miles | 0.313 | 0.545 |
| Three-test clean streak | 42.3% | 28.0% |
| Same advisory repeated 3+ times | 20.0% | 38.3% |
Care proxy is descriptive, not a claim about an owner's character: a clean streak means three or more consecutive tests with nothing recorded; the repeat measure means the same advisory appeared at least three times.
Safety recalls
| Model | Campaigns listed | Per 10,000 licensed |
|---|---|---|
| Mercedes A Class | 100 | 2.64 |
| Vauxhall Astra | 37 | 0.70 |
More campaigns do not by themselves mean a less reliable car: recalls are manufacturer remedies, and the licensed-fleet denominator is unavailable for some families. Check a registration for outstanding work before buying.
Do other countries see the same thing?
Both models appear in the same independent national inspection datasets below. Compare each model with that country's own average; absolute pass rates are not portable between rulebooks.
| Country / test | Model | Model fails | National average | Position | Inspections |
|---|---|---|---|---|---|
| Netherlands · APK | Mercedes A Class | 43.4% | 50.9% | -7.5 pp | 41,398 |
| Netherlands · APK | Vauxhall Astra | 53.0% | 50.9% | +2.1 pp | 69,587 |
Sources are the national PKK, Katsastus and APK datasets recorded in each family artifact. Position is model failure rate minus that country's national rate.
Quick answers
- Is the Mercedes A Class or the Vauxhall Astra more reliable?
- The Mercedes A Class has the stronger age-adjusted MOT result: index 91.3 against 109.1 for the Vauxhall Astra, with non-overlapping 95% confidence intervals.
- Does the Mercedes A Class or the Vauxhall Astra fail more MOTs?
- 18.83% of Mercedes A Class initial tests and 33.71% of Vauxhall Astra initial tests found a failing defect in 2024. The lower raw rate belongs to the Mercedes A Class, but the age-adjusted index is the fairer model comparison because the fleets can be different ages.
- What are the main MOT problem areas on the Mercedes A Class and Vauxhall Astra?
- The leading published failure group for the Mercedes A Class is suspension at 12.7 items per 100 tests; for the Vauxhall Astra it is lamps, reflectors and electrical equipment at 29.9 per 100.
- Should I buy a Mercedes A Class or a Vauxhall Astra?
- If MOT reliability is the deciding factor, the Mercedes A Class is the evidence-led choice. Still check the individual car's MOT history and condition: these figures describe whole model populations, not a particular vehicle.
Model pages and nearby comparisons
See the Kia Sportage and Nissan Qashqai comparisonSee the Mercedes A Class and Volkswagen Golf comparisonSee the Honda Jazz and Toyota Yaris comparison
Browse all car reliability comparisons.
How to read and cite this comparison
Scope: class-4 vehicles, initial tests only, Great Britain 2024. PRS fixed-on-the-spot results count as failures because a defect was present on arrival. Index = observed initial failures ÷ age-profile-expected failures × 100; intervals are 95% confidence intervals. Every model family combines all generations and engines. Full method: methodology.
Cite: MOT Risk Index (2026). Mercedes A Class vs Vauxhall Astra: MOT reliability comparison, 2024 (dvsa-2024-v1). https://motriskindex.co.uk/compare/mercedes-a-class-vs-vauxhall-astra/