What is the Gera Risk Comparison Delta (GRCD)?

The Gera Risk Comparison Delta (GRCD) is the signed difference between the Gera Vehicle Risk Index (GVRI) of two cars: GRCD = GVRI(Car A) − GVRI(Car B). A positive GRCD means Car A has a higher modelled insurance risk from real DVSA MOT data. A GRCD of zero means the two models carry identical measured risk in the 2016 dataset. Values range from −100 to +100.

How is the Gera Vehicle Risk Index (GVRI) computed?

GVRI = 0.6 × MOT_fail_rate + 0.4 × avg_defect_severity_norm, min-max scaled 0–100. MOT fail rate = failed tests ÷ total class-4 (car) normal tests. Defect severity = mean severity per failed test (1 = standard, 3 = dangerous item). All inputs are from the DVSA Anonymised MOT Test Results dataset (2016, OGL v3.0, 26,016,787 class-4 normal tests). Only combinations with N ≥ 30 tests are included. Full formula on the methodology page.

Does a larger GRCD mean the riskier car will always cost more to insure?

A larger GRCD reflects a measurably higher MOT fail rate and/or defect severity from real DVSA data, which correlates with claim risk and insurance pricing. However, insurers also weigh driver age, no-claims bonus, postcode, annual mileage, modifications and policy type. The GRCD is an objective, reproducible risk context from real test data — not a premium quote. Use it alongside other factors when comparing insurance costs.

Which car pair has the largest risk difference in the UK?

In the 2016 DVSA dataset, the Vauxhall Vectra (GVRI 60/100) vs Toyota Aygo (GVRI 23/100) shows the largest GRCD at 37 index points among our 200 tracked pairs. A 37-point gap represents a substantially different mechanical risk profile based on real MOT test outcomes.

What is the average GRCD across UK car comparisons?

Across 200 tracked comparisons derived from the top 50 most-tested UK cars in the 2016 DVSA dataset, the average absolute Gera Risk Comparison Delta is 18 index points. This means a typical comparison between two popular UK cars shows an approximately 18-point difference in GVRI — a meaningful but not extreme gap for most buyers.

Where does the data come from?

All GVRI values (and therefore all GRCD values) are computed from the DVSA Anonymised MOT Test Results dataset, published by the Driver and Vehicle Standards Agency under the Open Government Licence v3.0. The 2016 file contained 26,016,787 class-4 (car) normal MOT tests. The full formula is publicly reproducible — see the methodology page.

GeraSure / Car Insurance Risk Comparison

UK Car Insurance Risk Comparison by Make and Model

The Gera Risk Comparison Delta (GRCD) ranks 200 UK car pairs by the difference in their Gera Vehicle Risk Index (GVRI), computed from 26,016,787 DVSA MOT tests (2016, OGL v3.0). Maximum delta: 37 index points. UK fleet average GVRI: 37/100.

Which UK car is cheaper and safer to insure — how do models compare by risk?

Across 200 model-vs-model comparisons from 26,016,787 DVSA MOT tests (2016), the Gera Risk Comparison Delta (GRCD) reaches a maximum of 37 index points, with an average gap of 18 points between compared models. Source: DVSA Anonymised MOT data, OGL v3.0 (Gera Systems).

Source:DVSA Anonymised MOT Test Results — DfT·as of 2016updated annually (last: 20 June 2026)

Gera Risk Comparison Delta37 ptsMaximum GRCD across 200 UK car pairs — Vauxhall Vectra vs Toyota Aygo (2016 DVSA MOT data, OGL v3.0)How this index is calculated

Compare any two UK cars by insurance risk

Select two cars to see their Gera Risk Comparison Delta — the real GVRI difference from DVSA MOT data.

Car A

Make

Car B

Make

Select two cars to compare their Gera Risk Comparison Delta — computed from 26,016,787 real DVSA MOT tests.

Largest UK car risk differences by GRCD (2016 DVSA MOT data)

Top 15 UK car comparison pairs by Gera Risk Comparison Delta — DVSA MOT 2016 (OGL v3.0)
Car A	Car B	GRCD (pts)	Car A GVRI	Car B GVRI	Riskier car
Vauxhall Vectra	Toyota Aygo	+37	60/100 — High Risk	23/100 — Low Risk	Vauxhall Vectra
Honda Jazz	Vauxhall Vectra	-36	24/100 — Low Risk	60/100 — High Risk	Vauxhall Vectra
Renault Clio	Toyota Aygo	+35	58/100 — High Risk	23/100 — Low Risk	Renault Clio
Peugeot 206	Toyota Aygo	+35	58/100 — High Risk	23/100 — Low Risk	Peugeot 206
Vauxhall Vectra	Peugeot 107	+35	60/100 — High Risk	25/100 — Low Risk	Vauxhall Vectra
Peugeot 206	Honda Jazz	+34	58/100 — High Risk	24/100 — Low Risk	Peugeot 206
Renault Clio	Honda Jazz	+34	58/100 — High Risk	24/100 — Low Risk	Renault Clio
Peugeot 307	Toyota Aygo	+34	57/100 — High Risk	23/100 — Low Risk	Peugeot 307
Renault Clio	Peugeot 107	+33	58/100 — High Risk	25/100 — Low Risk	Renault Clio
Honda Jazz	Peugeot 307	-33	24/100 — Low Risk	57/100 — High Risk	Peugeot 307
Citroen Xsara Picasso	Toyota Aygo	+33	56/100 — High Risk	23/100 — Low Risk	Citroen Xsara Picasso
Honda Jazz	Citroen Xsara Picasso	-32	24/100 — Low Risk	56/100 — High Risk	Citroen Xsara Picasso
Vauxhall Vectra	Nissan Qashqai	+32	60/100 — High Risk	28/100 — Low Risk	Vauxhall Vectra
Fiat Punto	Toyota Aygo	+32	55/100 — High Risk	23/100 — Low Risk	Fiat Punto
Toyota Yaris	Vauxhall Vectra	-31	29/100 — Low Risk	60/100 — High Risk	Vauxhall Vectra

GRCD = GVRI(Car A) − GVRI(Car B). GVRI = 0.6 × MOT_fail_rate + 0.4 × avg_defect_severity_norm, 0–100. Source: DVSA MOT 2016, 26,016,787 class-4 normal tests, OGL v3.0.

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Browse car comparisons (200 pairs)

Individual comparison pages with Gera Risk Comparison Delta, MOT fail-rate difference, and side-by-side GVRI breakdown for 200 UK car pairs.

Showing 20 of 200 comparisons — use the tool above to compare any two cars.

UK car insurance risk comparison: frequently asked questions

What is the Gera Risk Comparison Delta (GRCD)?: The Gera Risk Comparison Delta (GRCD) is the signed difference between the Gera Vehicle Risk Index (GVRI) of two cars: GRCD = GVRI(Car A) − GVRI(Car B). A positive GRCD means Car A has a higher modelled insurance risk from real DVSA MOT data. A GRCD of zero means the two models carry identical measured risk in the 2016 dataset. Values range from −100 to +100.
How is the Gera Vehicle Risk Index (GVRI) computed?: GVRI = 0.6 × MOT_fail_rate + 0.4 × avg_defect_severity_norm, min-max scaled 0–100. MOT fail rate = failed tests ÷ total class-4 (car) normal tests. Defect severity = mean severity per failed test (1 = standard, 3 = dangerous item). All inputs are from the DVSA Anonymised MOT Test Results dataset (2016, OGL v3.0, 26,016,787 class-4 normal tests). Only combinations with N ≥ 30 tests are included. Full formula on the methodology page.
Does a larger GRCD mean the riskier car will always cost more to insure?: A larger GRCD reflects a measurably higher MOT fail rate and/or defect severity from real DVSA data, which correlates with claim risk and insurance pricing. However, insurers also weigh driver age, no-claims bonus, postcode, annual mileage, modifications and policy type. The GRCD is an objective, reproducible risk context from real test data — not a premium quote. Use it alongside other factors when comparing insurance costs.
Which car pair has the largest risk difference in the UK?: In the 2016 DVSA dataset, the Vauxhall Vectra (GVRI 60/100) vs Toyota Aygo (GVRI 23/100) shows the largest GRCD at 37 index points among our 200 tracked pairs. A 37-point gap represents a substantially different mechanical risk profile based on real MOT test outcomes.
What is the average GRCD across UK car comparisons?: Across 200 tracked comparisons derived from the top 50 most-tested UK cars in the 2016 DVSA dataset, the average absolute Gera Risk Comparison Delta is 18 index points. This means a typical comparison between two popular UK cars shows an approximately 18-point difference in GVRI — a meaningful but not extreme gap for most buyers.
Where does the data come from?: All GVRI values (and therefore all GRCD values) are computed from the DVSA Anonymised MOT Test Results dataset, published by the Driver and Vehicle Standards Agency under the Open Government Licence v3.0. The 2016 file contained 26,016,787 class-4 (car) normal MOT tests. The full formula is publicly reproducible — see the methodology page.

Methodology

The Gera Risk Comparison Delta is the difference between two Gera Vehicle Risk Index (GVRI) scores: GRCD = GVRI(Car A) − GVRI(Car B). GVRI is computed from DVSA Anonymised MOT Test Results (OGL v3.0): 0.6 × MOT_fail_rate + 0.4 × avg_defect_severity_norm, min-max scaled 0–100. Full formula and verification steps are on the methodology page.

Contains public sector information published by Driver and Vehicle Standards Agency (DVSA) and licensed under the Open Government Licence v3.0. Source: DVSA Anonymised MOT Test Results — DfT (2016, published 2016).