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Measurement and verification of energy results: urban street lighting

How to set up a measurement and verification plan to prove the results of a urban street lighting project.

Viale urbano e percorso ciclabile illuminati da apparecchi LED
Viale urbano e percorso ciclabile illuminati da apparecchi LED. Immagine illustrativa generata con AI.

Overview

A saving that cannot be demonstrated is a saving that can be disputed. The measurement and verification plan defines, before the works, how the result will be calculated, from which data and with which normalisations. The urban road network is the largest lit infrastructure managed by Italian municipalities and accounts for the biggest share of municipal energy spending.

Applicable standards

The regulatory reference for urban street lighting is not a single document but a coordinated set of standards covering performance, safety and environmental impact. In design practice the following documents drive the main choices.

  • EN 13201-2 — performance requirements for M, C and P classes.
  • EN 13201-3 — calculation of performance.
  • UNI 11248 — road classification and selection of lighting classes.

What an M&V plan contains

The plan defines the measurement boundary, the baseline period, the independent variables affecting consumption, the normalisation method, the instruments and reading frequency, plus each party's responsibilities. Agreeing it before the works prevents the method being chosen after the fact, when results are already known.

Which data to collect

You need consumption data granular enough to distinguish operating profiles, actual burning hours, maintenance events and configuration changes. Where a remote management system exists, most of these data are already available and only need structuring into recurring reports.

Data quality matters more than quantity: a continuous, verified series over a representative period is worth more than a large archive full of unexplained gaps.

Reporting over time

Periodic reporting has two functions: proving the result and detecting deviations early. Consumption departing from the forecast almost always signals a concrete issue — altered dimming profiles, undetected faults, usage changes — better addressed immediately than at period end.

Recurring critical points

The difficulties that most often emerge in urban street lighting projects are not about product selection, but about defining requirements and verifying results.

  • Classifying the road correctly, avoiding oversizing that turns into wasted energy.
  • Achieving uniformity and glare control on pole spacings inherited from legacy installations.
  • Meeting regional light-pollution limits without reducing perceived safety.

Design approach

An orderly method drastically reduces variations during works and disputes at commissioning. Three choices make the difference from the earliest stages.

  • Risk analysis per UNI 11248 with adaptive lighting classes.
  • Optics designed for the real carriageway geometry instead of generic distributions.
  • Flux regulation by time band and traffic, with profiles set during commissioning.

Parameters to verify

  • Lighting class — UNI 11248 / EN 13201-2 — set by risk analysis, not by road width
  • Overall uniformity U0 — EN 13201-2 — minimum requirement per class
  • Threshold increment TI — EN 13201-2 — to be verified in the calculation
  • ULOR — regional laws — upward flux to be brought to zero

Most frequent mistakes

Non-conformities found at commissioning almost always come from three causes: requirements not declared or declared without a reference standard, calculation run on idealised geometry, and an optimistic maintenance factor. All three can be avoided at zero cost during design.

Key takeaways

A urban street lighting project holds up over time when requirements are declared, the calculation reproduces real conditions and on-site verification follows an agreed protocol. Component selection matters, but comes later: without measurable requirements even the best product delivers a result that cannot be demonstrated. Centro Studi Lumeitalia makes its technical office available to review requirements and design checks.

Methodological note: This content is written for technical information purposes by Centro Studi Lumeitalia and does not replace the lighting design or a full reading of the standards cited. Applicable performance values are those of the standards in force at design time.

Domande frequenti

Who decides the lighting class of a road?+

The designer, through the risk analysis required by UNI 11248, based on traffic, vulnerable users, visual complexity and accident rate.

Can light levels be reduced at night?+

Yes. UNI 11248 allows adaptive regulation when risk parameters change, provided the profile is documented in the design and verifiable at commissioning.

Where should a urban street lighting project start?+

From a written definition of performance requirements and verification conditions: this step drives every later choice and makes the result either disputable or defensible at commissioning.

Which documents should be requested from the supplier?+

Photometric files of the proposed luminaires, declaration of conformity, lifetime data declared per IES LM-80 with its conditions, the maintenance schedule and warranty terms.