Publication
- Code: R 91
- Edition: 2025 (preview), superseding the 1990 edition
- Published by: Organisation Internationale de Métrologie Légale (OIML)
- Parts: R 91-1 requirements · R 91-2 test procedures · R 91-3 test report format · R 91-4 type evaluation report format
Scope
This Recommendation specifies metrological and technical requirements for traffic speed meters, the instruments used to measure the speed of road vehicles for enforcement. A measured speed under R 91 is evidence, and the Recommendation’s structure reflects that: vehicle identification certainty, image evidence, and the checking facilities that prevent a measurement the meter cannot trust.
It covers:
- Stationary and moving modes of use, fixed and mobile installations.
- The measuring principles in service: Doppler radar, range-finding, average-speed (section control), fixed-distance, image-based, and across-road technologies.
- Speed measuring intervals whose upper limit is at least 180 km/h (R 91-1 §6.1).
Accuracy structure
| Regime | MPE up to and including 100 km/h | MPE above 100 km/h |
|---|---|---|
| Stationary (§6.4) | ±3 km/h | ±3 % |
| Moving, class A (§6.15.1) | ±3 km/h | ±3 % |
| Moving, class B (§6.15.1) | ±7 km/h | ±7 % |
| Linearity (§6.5) | ±1 km/h | ±1 % |
The OIML certificate indicates the metrological class of a moving-mode meter. Relative units always bind to the absolute value of the reference speed (R 91-1 §3.5.2 NOTE).
SMART model coverage
- 57 requirements covering metrological, technical, and class-specific provisions.
- 64 conformance tests including the field tests and the full influence and disturbance battery.
- 78 report forms covering the R 91-3 test report and the R 91-4 type evaluation report.
- The full terminology (~70 terms).
The package is a preview edition: the model tracks the 2025 text and is superseded by the final edition when it publishes.
How to use it
| Goal | Path |
|---|---|
| Read the Recommendation overview | /recommendations/r91/ |
Cross-references
- D 31, General requirements for software controlled measuring instruments (the model’s software examination set).
- B 18, Framework for the OIML Certification System (the certification path the evaluation reports feed).
- The 1990 edition of R 91, superseded by the 2025 text.