- UN Regulation No. 129 (ECE R129) has been published in consolidated form in the EU Official Journal on 28 August 2026 as document 2026/1534.
- The text incorporates all amendments up to Supplement 4 to the 04 series, effective 4 June 2026.
- The regulation covers eight categories of child restraints with dynamic testing at 50 km/h (frontal), 30 km/h (rear), and 6.4–7.25 m/s (lateral).
- Rearward-facing is mandatory under 15 months; booster seats must ensure lateral protection up to 135 cm.
- From 1 September 2027, EU countries will no longer be obliged to accept approvals under preceding amendment series.
Background
The European Commission has published the consolidated text of UN Regulation No. 129 (ECE R129) in the Official Journal of the European Union under reference 2026/1534, dated 28 August 2026. The document compiles all valid legal texts of the regulation establishing uniform provisions concerning the approval of Enhanced Child Restraint Systems (ECRS) used on board motor vehicles. The text incorporates all amendments up to Supplement 4 to the 04 series of amendments, which entered into force on 4 June 2026.
The regulation is a central instrument within the UN/ECE system for harmonised vehicle regulations and forms the technical basis for i-Size requirements for child seats in the EU and in all other Contracting Parties to the 1958 Agreement.
Scope and categories
The regulation covers eight categories of child restraint systems:
| Category | Description |
|---|---|
| i-Size (integral, universal ISOFIX) | Designed for all i-Size seating positions |
| Specific vehicle ISOFIX (integral) | For specific vehicle types |
| i-Size booster seat (non-integral) | With backrest and optional ISOFIX attachments |
| Specific vehicle booster seat (non-integral) | For specific vehicle types |
| Universal Belted (integral) | Secured exclusively by adult safety belt |
| Specific vehicle Belted (integral) | Secured by safety belt in specific vehicles |
| Universal booster cushion (non-integral) | Without backrest, for all i-Size and universal positions |
| Specific vehicle booster cushion (non-integral) | Without backrest, for specific vehicles |
Positioning and safety requirements
The regulation establishes a number of key safety requirements:
- Rearward-facing mandatory: Children under 15 months must exclusively travel in rearward-facing or lateral-facing child restraints. A rearward-facing restraint designed for children up to 15 months must accommodate a child with a stature of at least 83 cm. Forward-facing restraints must not be designed for children below 76 cm.
- Infant carrier: May accommodate children up to a maximum stature of 87 cm.
- Booster cushion: Must not be approved below 125 cm stature. Sitting height must ensure the child's head is at least 770 mm above the Cr axis.
- Non-integral systems: Must not be approved below 100 cm stature and must ensure lateral protection up to 135 cm.
- Mass limit: An integral ISOFIX child restraint combined with the largest child must not exceed 33 kg.
Dynamic test requirements
The regulation mandates extensive dynamic tests for frontal, rear, and lateral impact:
| Test type | Speed/velocity change | Stopping distance |
|---|---|---|
| Frontal impact (sled) | 50 +0/-2 km/h or ΔV 52 km/h | 650 ± 50 mm |
| Rear impact (sled) | 30 +2/-0 km/h or ΔV 32 km/h | 275 ± 25 mm |
| Lateral impact | Relative velocity 6.375–7.25 m/s | Max. intrusion 250 ± 50 mm |
Tests are conducted using Q-dummies (Q0, Q1, Q1.5, Q3, Q6, and Q10) representing 50th percentile children aged 0, 1, 1.5, 3, 6, and 10.5 years. Injury criteria include:
| Criterion | Limit value |
|---|---|
| Resultant head acceleration (3 ms) | 75–80 g |
| Head Performance Criterion (HPC) | 600–800 |
| Resultant chest acceleration (3 ms) | 55 g |
| Abdominal pressure | 1.0–1.2 bar |
During dynamic tests, no part of the child restraint system affecting the restraint of the occupant shall fully or partially fracture, and no buckle, locking system or displacement system shall release or unlock — unless such parts are identified as having a load-limiting function in the manufacturer's technical description.
Material and flammability requirements
- Toxicity: Materials accessible to the child must comply with EN 71-3:2019+A1:2021 (Category III). This requirement does not apply to non-integral ECRS with a stature range of 100 cm or above.
- Flammability: Materials must comply with EN 71-2:2020 with a maximum rate of spread of flame of 30 mm/s for non-built-in systems. For built-in systems, materials must not burn at a rate exceeding 100 mm/min.
- Corrosion: Metal parts must undergo a 50 ± 0.5 hour salt fog test at 35 °C.
- Straps: Breaking load of at least 3.6 kN. At least 75% of breaking load after conditioning with cold, heat, water, light, and abrasion.
- Buckles: Must withstand 4 kN (mass limit ≤ 13 kg) or 10 kN (mass limit > 13 kg). Opening force: 40–80 N without load, maximum 80 N under load.
ISOFIX and anti-rotation devices
The regulation specifies detailed requirements for:
- ISOFIX attachments: Minimum 2,000 ± 5 opening/closing cycles. Locking mechanism must require two consecutive actions or an opening force of at least 50 N.
- Top tether: Length of at least 2,000 mm with a no-slack indicator.
- Support-leg: Contact surface of at least 2,500 mm², minimum outside dimensions 30 mm, edge radius minimum 3.2 mm. Adjustment increment maximum 20 mm.
- Lower tether: Length of at least 900 mm including connector.
Marking and user instructions
Every child restraint system must bear:
- Approval mark with "E" circle, approval number, and regulation number
- i-Size logo (minimum 25 x 25 mm) for i-Size categories
- Size range in centimetres
- Maximum occupant mass in kilograms
- Warning label for rearward-facing restraints (minimum 120 x 60 mm) with airbag danger pictogram
- Belt route marking in green
- Quick-start guide on paper with QR code to digital user instructions
If a manufacturer does not provide a paper version of the user instructions, a QR code or web link must be permanently affixed to the child restraint. The digital instructions must be available for at least 10 years after production has been definitively discontinued.
Production conformity and transitional provisions
Production conformity is monitored through:
- Batch control with dual sampling (normal and strengthened control)
- Continuous control: 1 sample per 5,000 units (normal) or 1 per 2,000 (strengthened)
- For "specific vehicle" restraints: Test every eight weeks (reducible to 16 weeks)
Transitional provisions stipulate that from 1 September 2026, Contracting Parties are no longer obliged to accept UN type-approvals issued after 1 September 2026 under preceding series of amendments. From 1 September 2027, the same applies to all previously issued type-approvals.
Next phase
According to information from the UN World Forum for Harmonization of Vehicle Regulations (WP.29), proposals for a 05 series of amendments to the regulation have already been submitted, including updated shoulder height requirements for small children and revised transitional provisions with a new deadline of 1 September 2028.