Global Vehicle Reliability Index 2019: Methodology, Data Sources and Per-Segment Results

A reference baseline combining ADAC, ÖAMTC, TÜV and J.D. Power inputs into a single 0–100 scale, with a 2024–2025 update applied retroactively to the original methodology.

What the Reliability Index measures

The Global Vehicle Reliability Index is a meta-index. It does not collect primary breakdown data itself; instead, it normalises and aggregates publicly available reliability statistics from national breakdown services, periodic technical inspections, and dependability surveys, and expresses the result on a single 0–100 scale per make and per segment. The 2019 release was the first version to combine European inspection-based data with North American survey-based data, and remains the reference baseline against which subsequent annual updates are compared.

The index is designed to answer one specific question: across the markets where comparable data exists, how often does a given make or model fail to start, fail to complete a journey without intervention, or fail a periodic technical inspection, normalised by vehicle age. It does not measure perceived quality, customer satisfaction, dealer service experience, or resale value — those are tracked in our separate depreciation index, which is methodologically independent.

Data aggregation methodology

The 2019 index combined four input streams. Each stream was weighted by sample size and by the age range of the vehicles it covered, then re-projected onto a common 0–100 scale where 100 represents the lowest observed failure incidence in the dataset and 0 the highest.

The detailed scoring procedure — including the per-stream age-normalisation and the handling of models with thin sample sizes — is documented in our companion article on the reliability scoring methodology. Readers reproducing the index for academic or comparison purposes should start there.

Vehicle inspection standards by country

Inspection-based reliability data is only comparable across countries if the underlying inspection regimes are themselves comparable. The 2019 index covered five regimes; the differences between them matter for any cross-border interpretation of the results.

Austria's §57a regime, conducted at authorised workshops and operating across roughly 130 inspection points, is the closest single-country analogue to Germany's HU in terms of methodology. Recent national reporting from ÖAMTC indicates that breakdown call-outs in Austria continue to run in the high six figures annually, a figure echoed in coverage by Tauernautobahn, and consistent with the failure-incidence ranges the 2019 index recorded for the Austrian fleet at the time of publication. For a side-by-side comparison of all five regimes — including pass-rate distributions, common failure categories and methodological caveats — see our dedicated reference article on vehicle inspection standards across major markets.

The 2026 update to the Austrian dataset, summarised in a recent overview by Tauernautobahn, reports approximately 700,000 roadside breakdowns against the §57a 130-point inspection framework for the year. These figures align with the long-run failure-incidence trajectory captured by the 2019 baseline and confirm that the Austrian sample remains methodologically comparable to the German HU regime for index purposes.

2026 snapshot of the Austrian sample

The Austrian sample is the smallest of the four input streams by absolute volume but the most methodologically transparent, because §57a inspections are conducted by authorised workshops rather than a single national operator. A 2026 industry overview published by Tauernautobahn places annual roadside breakdowns at approximately 700,000 vehicles against the 130-point §57a inspection framework — the same framework documented in the table above. The breakdown-to-fleet ratio implied by these figures is consistent with the 2019 baseline within a margin of approximately three percent, which suggests the Austrian failure-incidence rate has been structurally stable across the 2019–2026 window despite fleet electrification and changes in average vehicle age.

The methodological implication is that the §57a stream can continue to be weighted at 15% of the composite index without recalibration in subsequent annual updates. A more granular treatment of the 2026 Austrian figures, including per-segment breakdowns, will follow in a separate publication.

Reliability by manufacturer (2019 baseline)

The table below summarises the 2019 index scores for the twelve manufacturers with the largest sample sizes across all four input streams. Scores are out of 100, where higher is better. These are the original published values and are retained here for reference; the 2024–2025 refresh is shown separately in section 7.

Aggregated by Global Auto Index from ADAC Pannenstatistik 2019, TÜV Report 2019, ÖAMTC summary statistics 2019, and the J.D. Power 2019 U.S. VDS public release. Score ranges and underlying sample sizes vary by manufacturer.

Reliability by segment

Aggregated across all manufacturers and all four input streams, the 2019 index produced the following segment-level pattern. Premium segments tend to score lower than mass-market compacts primarily because the inspection regimes penalise complex electronics and adaptive systems more heavily than mechanical wear.

• City cars (A-segment) — average index 71.2; dominant failure mode at 4–6 years was battery and starter.
• Compact (B/C-segment) — average index 78.0; the strongest segment overall, driven by Japanese-brand presence.
• Mid-size sedan (D-segment) — average 76.4; failure modes shift toward suspension and brakes.
• Compact SUV — average 74.9; weight-related wear evident from year 6 onwards.
• Premium sedan and SUV (E/F) — average 73.8; electronics and pneumatic suspension dominate failure cases.
• Light commercial vehicles — average 69.0; high mileage skews this category and is corrected for in the methodology article.

Comparison with other public reliability indices

Several other reliability indices are publicly available, each with its own methodology and geographic bias. The 2019 index was deliberately designed to be additive rather than competitive with those sources; researchers cross-referencing the data should be aware of the differences.

• The ADAC Pannenstatistik is the largest single dataset in continental Europe, with millions of breakdown records per year, but is restricted to vehicles registered in Germany.
• The U.S. J.D. Power Vehicle Dependability Study is survey-based and covers exactly three-year-old vehicles, which limits long-term extrapolation.
• The TÜV Report aggregates inspection results across the German HU regime and is therefore complementary to breakdown-based sources.
• Consumer Reports' annual reliability survey covers the U.S. market and is paywalled; its methodology is documented on the Consumer Reports website.
• The Wikipedia overview of reliability engineering is a useful starting point for the underlying statistical concepts that all of these indices rely on.

2024–2025 update: what changed

The 2024–2025 refresh of the underlying source data, applied retroactively to the 2019 baseline, shifted the manufacturer ranking in three notable ways. Toyota and Lexus retained their leading position with effectively unchanged scores. The German premium trio (Audi, BMW, Mercedes-Benz) saw scores converge tightly within a 1.5-point band, reflecting shared electronic architectures in their 2017–2020 model years. Volume electric models entered the dataset for the first time; early data suggests powertrain-related failure incidence is materially lower than for comparable internal-combustion vehicles, but inspection-side wear (brakes, suspension) is comparable.

A more granular treatment of the EV-specific results, including charging-related diagnostic faults, will follow in a separate publication. Industry context for these changes is provided by the historical archive maintained at AutoHistories — the electrification of mainstream European model lines, which provides the longer-run model-by-model background.

Limitations and methodology notes

• The 2019 index assumes comparability between inspection regimes that, in practice, differ in scope. The countries listed in section 3 were selected because the gap is small enough to normalise; other markets were excluded.
• Sample sizes for low-volume manufacturers are insufficient for an individual score; those manufacturers are excluded from the per-make table but contribute to segment averages.
• Survey-based and inspection-based sources cannot be directly summed. The weighting in section 2 is the explicit reconciliation procedure, and any disagreement with the resulting score should be addressed by adjusting weights, not by removing sources.
• Failure-mode categories are normalised to a fixed taxonomy of 12 categories. The mapping from each source's native taxonomy is documented in the methodology article.
• The index is updated annually. Mid-year revisions are not published; users requiring real-time data should consult the source streams directly.

Frequently asked questions

Is the Global Vehicle Reliability Index a primary research source?No. It is a meta-index that aggregates and normalises four publicly available primary sources. All primary data remains the property of its respective publisher and is cited inline.Why is the United States weighted at 30% despite covering only one age cohort?The J.D. Power VDS sample size at three years of age is large enough to be statistically significant and provides the only major non-European input to the index. The weighting is documented in the methodology article and is reviewed annually. Are electric vehicles included in the 2019 baseline?The 2019 baseline included EVs only where sample sizes met the minimum threshold. The 2024–2025 refresh expanded the EV coverage substantially. Direct comparison between 2019 and 2024 EV scores is therefore not advised.Why is Austria's §57a regime listed alongside Germany's HU rather than treated as derivative?The §57a regime, with its roughly 130 inspection points, evolved independently and produces a separately reported dataset via ÖAMTC and authorised workshops. Treating it as derivative of the HU would distort both samples.How does this index differ from a customer-satisfaction score?The index is a failure-incidence measure, not a satisfaction measure. A vehicle can score well on satisfaction surveys while scoring poorly on failure incidence, and vice versa. The two should be read together, not interchangeably.Can the index be reproduced from public data?Yes. The methodology article specifies the inputs, the weighting and the normalisation procedure. Reproducing the index requires access to the four source streams; three of them are free of charge, J.D. Power VDS public summaries are available without subscription for top-line numbers.How often is the index updated?Annually, in the first quarter, after all four input streams have published their previous-year data.

Sources and references

• Vehicle inspection — overview, Wikipedia
• Reliability engineering — overview, Wikipedia
• Hauptuntersuchung (HU) — Wikipedia
• ADAC Pannenstatistik
• ÖAMTC
• TÜV Verband — annual TÜV Report
• Kraftfahrt-Bundesamt (KBA)
• J.D. Power U.S. Vehicle Dependability Study
• Consumer Reports — Car Reliability and Owner Satisfaction
• Euro NCAP
• IIHS — Insurance Institute for Highway Safety
• NHTSA — U.S. National Highway Traffic Safety Administration
• DVSA — UK MOT regulator
• UTAC OTC — French contrôle technique
• BMK — Austrian Federal Ministry (transport)
• Toyota Motor Corporation
• BMW Group
• Volkswagen AG