Short answer: motorised traffic roads use M classes, set by road luminance: from 2.0 cd/m² (M1) down to 0.3 cd/m² (M6). Conflict areas such as junctions use C classes, from 50 down to 7.5 lux. Residential streets, paths and car parks use P classes, from 15 down to 2 lux. The class comes from speed, traffic, users and surroundings, and it sets the lumens each pole must deliver.
Most tenders in Africa and Asia cite CIE 115 or the European EN 13201 series, which share the same class system. Getting the class right first avoids the two common mistakes: oversized lights that waste budget, and undersized lights that fail the acceptance measurement.
Key numbers
- M classes (EN 13201-2): average road luminance from 2.0 cd/m² (M1) to 0.3 cd/m² (M6), with overall uniformity of at least 0.35–0.40.
- C classes: average illuminance from 50 lux (C0) to 7.5 lux (C5), uniformity at least 0.40.
- P classes: average illuminance from 15 lux (P1) to 2 lux (P6), with a minimum point of 20 % of the average.
1. M classes: roads for motorised traffic
On roads where drivers see obstacles against the road surface, the requirement is luminance (brightness of the road as seen by the driver), not illuminance on the ground.
| Class | Average luminance L̅ (cd/m², min) | Overall uniformity Uo | Longitudinal uniformity Ul | Threshold increment fTI (%, max) |
|---|---|---|---|---|
| M1 | 2.00 | 0.40 | 0.70 | 10 |
| M2 | 1.50 | 0.40 | 0.70 | 10 |
| M3 | 1.00 | 0.40 | 0.60 | 15 |
| M4 | 0.75 | 0.40 | 0.60 | 15 |
| M5 | 0.50 | 0.35 | 0.40 | 15 |
| M6 | 0.30 | 0.35 | 0.40 | 20 |
Threshold increment limits glare. Uniformity matters as much as the average: a design that reaches 1.0 cd/m² with dark patches between poles fails M3.
2. C classes: junctions and conflict areas
Roundabouts, intersections, shopping streets and areas where vehicles meet pedestrians and cyclists use illuminance on the ground. A conflict area is normally lit one class step above the approach roads.
| Class | C0 | C1 | C2 | C3 | C4 | C5 |
|---|---|---|---|---|---|---|
| Average illuminance (lux, min) | 50 | 30 | 20 | 15 | 10 | 7.5 |
| Overall uniformity Uo | 0.40 for all classes | |||||
3. P classes: residential streets, paths and car parks
| Class | P1 | P2 | P3 | P4 | P5 | P6 |
|---|---|---|---|---|---|---|
| Average illuminance (lux, min) | 15 | 10 | 7.5 | 5 | 3 | 2 |
| Minimum point (lux) | 3.0 | 2.0 | 1.5 | 1.0 | 0.6 | 0.4 |
P classes are where most solar street lights work, because the energy needed is modest. Our sizing guide starts from these values.
4. How the class is chosen
EN 13201-1 and CIE 115 select the class from weighted parameters rather than from road names. The main ones:
- Design speed: higher speed, higher class.
- Traffic volume and mix: heavy traffic, cyclists and pedestrians on the carriageway raise the class.
- Junction density, parked vehicles and a central reserve all change the weighting.
- Ambient brightness: a bright town centre needs more than a dark rural road for the same visibility.
- Facial recognition and crime risk on pedestrian routes push P classes up.
As a starting point, typical choices are:
| Road or area | Typical class |
|---|---|
| Urban dual carriageway, ring road, high traffic | M2–M3 |
| Urban main road, collector road | M3–M4 |
| Rural main road, low traffic | M4–M5 |
| Roundabout, signalised junction | C1–C3 |
| Town-centre street, market road | C3–C4 or P1 |
| Residential street | P3–P4 |
| Village road, footpath, park | P4–P6 |
This mapping is our engineering guidance. Where the tender names a class, use it; where it names only a lux figure, check which class it corresponds to.
5. From class to lumens per pole
For a quick check, the luminaire flux each pole must deliver is: average illuminance × road width × spacing ÷ (utilisation factor × maintenance factor). For M classes, convert luminance to illuminance with the road surface: on typical dry asphalt, 1 cd/m² corresponds to roughly 12–15 lux. That conversion is a rule of thumb only; a luminance design must be calculated with the luminaire’s IES file.
| Class | Road and spacing | Average lux used | Luminaire lumens needed | LED power at 140 lm/W |
|---|---|---|---|---|
| P4 | 6 m road, 25 m spacing | 5 | about 1,900 lm | about 14 W |
| P2 | 6 m road, 25 m spacing | 10 | about 3,750 lm | about 27 W |
| P1 | 6 m road, 25 m spacing | 15 | about 5,600 lm | about 40 W |
| M5 | 7 m road, 30 m spacing | about 7 | about 3,700 lm | about 26 W |
| M4 | 7 m road, 30 m spacing | about 11 | about 5,800 lm | about 41 W |
| M3 | 7 m road, 30 m spacing | about 14 | about 7,400 lm | about 53 W |
| M2 | 7 m road, 30 m spacing | about 21 | about 11,000 lm | about 79 W |
Our own calculation, single-sided poles, utilisation factor 0.5 and maintenance factor 0.8. Real designs vary with optics, mounting height and road surface, but the table shows why an M3 road rarely needs the 150 W fittings often specified, while a P4 residential street is well within the reach of an all-in-one solar light.
6. Acceptance: how the light is checked
EN 13201-3 sets the calculation grid and EN 13201-4 the measurement method. On site, inspectors usually measure illuminance on a grid between two poles with a calibrated lux meter. Ask your supplier for the calculation report for your exact road, made with the IES file of the luminaire being offered, so that the design and the measured result can be compared.
FAQ
How many lux does a main road need?
Main roads are specified in luminance, typically M3 (1.0 cd/m²) for an urban main road, which corresponds roughly to 12–15 lux on dry asphalt. Busy dual carriageways use M2 (1.5 cd/m²).
How many lux for a residential street?
Usually P3 or P4: 7.5 or 5 lux average, with a minimum point of 1.5 or 1.0 lux.
What is the difference between CIE 115 and EN 13201?
CIE 115 is the international recommendation; EN 13201 is the European standard built on the same classes. Tenders in Africa and Asia cite either, and the class tables match.
Is uniformity really that important?
Yes. A design can meet the average and still fail, because dark gaps between poles reduce visibility. Uniformity also limits how far apart poles can go; see our pole height and spacing guide.
How we help
Send us the road width, the lighting class or lux target, and the pole layout. We will propose the luminaire from our LED street lights or solar street lights, and provide the IES file so the design can be checked.
Sources: EN 13201-2:2015 performance requirements (M, C and P class tables); EN 13201-1 and CIE 115:2010 class selection parameters; EN 13201-3 and -4 calculation and measurement methods. The luminance-to-illuminance rule of thumb, the class mapping and the lumens table are our own engineering guidance. Related: all-in-one vs split, spec-sheet checks.