Publication
- Code: R 129
- Edition: 2000 (E)
- Published by: Organisation Internationale de Métrologie Légale (OIML)
- Custodian: OIML Technical Committee TC 9 (Instruments for measuring mass and density)
Scope
This Recommendation specifies metrological and technical requirements for automatic weighing instruments that dynamically determine the mass of road vehicles, axle-loads of road vehicles, or both, while the vehicles are in motion.
It applies to WIM systems installed either:
- Permanently in the road surface (fixed WIM systems).
- As portable devices for enforcement (portable WIM systems).
Accuracy classes
| Class | Tolerance | Typical use |
|---|---|---|
| 0.2 | ±0.2% | High-precision static-equivalent measurement |
| 0.5 | ±0.5% | Enforcement (precision) |
| 1 | ±1.0% | Enforcement (standard) |
| 2 | ±2.0% | Statistics, infrastructure planning |
| 5 | ±5.0% | Coarse screening |
| 10 | ±10% | Indicative only |
SMART model coverage
- 35 requirements with structured acceptance criteria.
- 14 conformance tests including the dynamic-vs-static comparison procedures.
- 9 test report forms with statistical aggregation across runs.
- The full terminology (~50 terms).
A distinctive feature of the R 129 SMART model: dynamic tests produce distributions of measurements across multiple runs and speeds, requiring statistical aggregation computations (max, mean, std-dev) inside the forms.
How to use it
| Goal | Path |
|---|---|
| Browse the structured requirements | the SMART Recommendations browser ↗ |
| Read the Recommendation overview | /recommendations/r129/ |
| Download the source PDF | oiml.org ↗ |
Cross-references
- R 134, Automatic instruments for weighing road vehicles in motion and axle-load measuring (companion standard).
- D 30, Application of ISO/IEC 17025 to testing laboratories.