Less light when the streets are quiet.
Learning Track · Module 4: Energy and carbon · Step 25 of 101
Showing content for Europe. Change the region at the top of the page.
Europe: EN 13201 lets you use a lower class when traffic is lower, for example M3 in the evening and M5 after midnight.
Middle East: Check the authority manual. Many allow dimming on residential and secondary roads late at night. Highways often stay at full level.
South Asia: IS 1944 does not define adaptive classes. Many smart city tenders still specify dimming, usually to 50% to 70% late at night on secondary roads.
USA: RP-8 supports adaptive lighting: a lower level when pedestrian and vehicle activity is lower. Agree the levels with the road owner and the utility.
| Time | Example level |
|---|---|
| Sunset to 22:00 | 100% |
| 22:00 to 05:30 | 50% |
| 05:30 to sunrise | 100% |
Ways to dim
- Driver profile: fixed steps or virtual midnight. No controller needed.
- Node: DALI or 0–10 V commands. Change the schedule at any time.
- Cabinet voltage reduction: works for old discharge lamps, but does little for most LED drivers.
At each step time, circuit power must change. OpenSLMS compares power with the schedule and shows each missed step. Calculate the saving with the dimming calculator.
Sources
- CEN/TR 13201-1 Guidelines on selection of lighting classes
- ANSI/IES RP-8
Changes: 30 October 2026: First publication: guides for Europe, the Middle East, South Asia, and the USA; failure library; tender clause library; comparisons; tools; downloads. See the changelog. Found a mistake? Report it.