3. Protocol-year architecture

Global NCAP is not a single, frozen test specification. It is a continuously evolving assessment programme, and every vehicle is evaluated against a specific protocol year. Understanding how protocol versions are numbered, when they are released, how vehicles migrate between them, and how a compliance decision is anchored to one particular year is essential for anyone interpreting star ratings, planning a test programme, or defending a result to a regulator or customer. This section explains that architecture and shows how to determine compliance against a named protocol year in practice.

Why protocol years exist

Crash safety knowledge advances: dummy instrumentation improves, new body regions are assessed, rating thresholds tighten, and test procedures are refined to close loopholes. If the programme changed silently, a five-star result from 2018 could be compared misleadingly with a five-star result from 2024. The protocol-year construct solves this by making every requirement, threshold, and procedure traceable to a dated, published specification. A rating is therefore always a statement of the form "this vehicle, tested to this protocol year, achieved this score."

The versioning logic follows a predictable pattern. The primary identifier is the calendar year of the specification (e.g., Protocol Year 2023, 2024, 2025). Within a year, minor revisions may be issued as point releases (e.g., 2024.1, 2024.2) to correct errata, clarify ambiguous wording, or adjust a reference document without changing the fundamental assessment structure. Major structural changes — a new assessment area, a re-weighted scoring model, or a revised star threshold — are reserved for a new protocol year. This separation matters: a point release should never silently move a vehicle across a star boundary, whereas a new protocol year legitimately can.

Release cadence and the publication window

Global NCAP publishes its forward programme on a rolling basis. In practice, the next protocol year's specification is released well ahead of its effective date — typically six to twelve months — so that manufacturers can engineer and validate vehicles against it. The release cadence has three practical consequences for a test programme:

  • Design freeze alignment. A vehicle whose design freeze falls before the new protocol's publication will almost certainly be assessed to the outgoing year; one freezing after publication should be planned against the incoming year.
  • Test-slot planning. Laboratories book crash slots months in advance. Knowing which protocol year applies determines which dummy configurations, sled pulses, and instrumentation channels must be reserved.
  • Documentation currency. The assessment report must cite the exact protocol year and point release used. Citing "latest protocol" is not acceptable because "latest" changes over time.
Always record the protocol year and the point release (e.g., "Global NCAP Protocol Year 2024, Rev. 2024.2") in the test request, the lab work order, and the final report. This single habit prevents most retrospective compliance disputes.

Transition rules: which year applies to a given vehicle

The transition rules define the boundary between protocol years. The governing principle is that the applicable protocol year is fixed at the point of test entry, not at the point of sale or type approval. A vehicle entered into the programme before the new protocol's effective date is assessed to the outgoing year; a vehicle entered on or after that date is assessed to the incoming year. Manufacturers cannot cherry-pick the more favourable year once a test entry is lodged.

There are, however, legitimate transition provisions. A commonly applied rule allows a vehicle already tested to the outgoing year to retain that rating for a defined validity period, provided no significant design change occurs. If the vehicle is facelifted — a changed front structure, a new restraint calibration, or a modified body-in-white — the rating is normally voided and the vehicle must be re-entered against the current protocol year. The table below summarises the decision logic.

Scenario Applicable protocol year Action required
Test entry lodged before new year's effective date Outgoing year Proceed; cite outgoing year in report
Test entry lodged on/after effective date Incoming year Re-plan dummy, instrumentation, and thresholds
Existing rating, no design change, within validity period Original year retained Monitor validity expiry
Facelift or structural change to a rated vehicle Current year at re-entry Void old rating; re-test

How compliance is determined against a specific protocol year

Compliance is not a single pass/fail gate; it is a structured determination against the requirements of the named year. The process has four linked steps, illustrated in the diagram below.

1. Fix protocol year Entry date + point release e.g. PY2024 Rev.2 2. Extract requirements Dummies, pulses, channels Thresholds & weightings 3. Execute & measure Crash tests, dummy data Injury criteria computed 4. Score & decide Compare to thresholds Assign star rating Non-conformance: re-check year, procedure, or re-test Compliance evidence per protocol year Requirement set Frontal ODB 64 km/h Side MDB 50 km/h Pedestrian & child Active safety items Measured criteria HIC, chest deflection Femur / tibia loads Head excursion AEB performance Decision basis Threshold table of PY Weighted sub-scores Star boundary check Report cites PY + Rev.

Step 1 — Fix the protocol year. Determine the applicable year from the test-entry date and record the point release. This is the anchor for everything that follows.

Step 2 — Extract the requirement set. From the named protocol year, pull the exact test configurations (e.g., frontal offset deformable barrier at 64 km/h, side mobile deformable barrier at 50 km/h), the dummy types and instrumentation channels, the injury criteria, and the scoring weightings. These differ between years, so the extraction must be done from the correct document, not from memory or a previous report.

Step 3 — Execute and measure. Run the tests to the specified procedures and compute the injury criteria from the recorded channels. For example, head injury criterion is derived from the resultant head acceleration time history over the specified window; chest deflection is read from the rib potentiometers. Each computed value is a candidate input to the scoring model.

Step 4 — Score and decide. Apply the protocol year's threshold table and weightings to convert measured criteria into sub-scores, sum them, and compare the total against the star boundaries defined for that year. A vehicle is compliant with the protocol year when every mandatory requirement is met and the total score reaches the threshold for the claimed star rating.

A worked compliance check (illustrative example)

Consider a hypothetical vehicle entered under Protocol Year 2024, Rev. 2024.2. The frontal offset test yields a driver HIC of 540 and a chest deflection of 32 mm. The 2024 threshold table sets the HIC limit for full marks at 650 and the chest deflection limit at 42 mm; both measured values sit inside the full-mark band, so the frontal sub-score is at its maximum. Suppose the side test returns a chest deflection slightly above the full-mark limit but below the zero-mark limit, producing a partial sub-score. The weighted total is then compared with the 2024 star boundaries. If the total clears the five-star boundary and all mandatory items pass, the vehicle is recorded as five stars to PY2024 Rev.2. The same measured data scored against a stricter later year might fall short — which is precisely why the protocol year must be stated alongside the result.

A common failure mode is scoring measured data against the wrong year's threshold table — often because a previous report was reused as a template. The symptom is a plausible-looking score that cannot be reproduced when the correct protocol document is applied. Always re-extract thresholds from the cited year and cross-check the point release before signing the report.

In summary, the protocol-year architecture gives Global NCAP its comparability and its forward momentum: versioning separates minor corrections from structural change, the release cadence aligns engineering timelines with assessment timelines, transition rules fix the applicable year at test entry, and compliance is a traceable determination of measured criteria against the threshold table of one named protocol year. Treat the protocol year and point release as first-class data in every test record, and the rest of the compliance chain remains auditable.

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