Lumeitalia

Reference project: how we set up a motorway and major-artery lighting intervention

The working method applied by the Lumeitalia technical office to a motorway and major-artery lighting intervention, stage by stage.

Studio illuminotecnico con planimetria, ottiche e simulazione della luce
Studio illuminotecnico con planimetria, ottiche e simulazione della luce. Immagine illustrativa generata con AI.

Overview

This piece describes a design method, not a specific site: the values given are setup criteria, not measurements from a built installation. On motorways and main extra-urban roads, lighting is concentrated on interchanges, service areas and high-risk sections, where visual continuity is a safety requirement. The aim is to make repeatable the sequence of decisions that takes a motorway and major-artery lighting intervention from survey to commissioning.

Applicable standards

The regulatory reference for motorway and major-artery 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 — M classes for fast motorised traffic.
  • CIE 140 — road lighting calculation methods.
  • UNI 11248 — class selection and adaptive downgrading.

Stage 1 — Survey of the existing condition

The survey precedes any solution hypothesis. Real geometry, position and height of existing luminaires, condition of poles and lines, installed power, operating hours and issues reported by the operator are all recorded. The photographic survey documents the initial state and is the basis for the before/after comparison.

In motorway and major-artery lighting contexts the survey must include the conditions that constrain the solution: avoiding abrupt transition zones between lit and unlit sections and access limitations for future maintenance.

Stage 2 — Requirements and calculation assumptions

Requirements are declared in writing with their reference standard and the rationale for the chosen category. The same note fixes the maintenance factor, the assumed cleaning cycle and the ambient conditions considered. This is the document that makes the design verifiable and that, in a dispute, separates an execution error from a requirement never agreed.

Stage 3 — Solution selection

Selection starts from the photometric distribution suited to the surveyed geometry, then considers environmental compatibility, the control system and maintainability. At least two alternative configurations are assessed with their impact on luminaire count, installed power and maintenance burden: a documented comparison is what makes the final choice defensible.

Stage 4 — Verification and handover

On-site verification follows the protocol agreed in the specification and closes with a report comparing measured values against declared requirements. At handover the updated calculation report, photometric files of the installed luminaires, maintenance plan and control system configuration are transferred. Without this package, later operation starts from scratch.

Performance data from a real intervention can only be shared if measured and authorised by the client: for this reason the method is described here without site figures. Project-specific documentation is available on request from the technical office.

Recurring critical points

The difficulties that most often emerge in motorway and major-artery lighting projects are not about product selection, but about defining requirements and verifying results.

  • Avoiding abrupt transition zones between lit and unlit sections.
  • Keeping maintenance feasible with minimal lane closures.
  • Withstanding vibration, de-icing salt and wind loads on high masts.

Design approach

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

  • Transition zones designed with a controlled luminance gradient.
  • Luminaires with fast access to the gear tray and replaceable components.
  • Remote management for diagnostics and fewer field interventions.

Parameters to verify

  • M class — EN 13201-2 — assigned by design speed and complexity
  • Surround ratio SR — EN 13201-2 — lighting of the lateral strips
  • Maintainability — specification — access without removing the optic
  • Mechanical resistance — EN 60598 — vibration and pole loads

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.

  • Geometric, electrical and photographic survey of the existing condition
  • Requirements declared in writing with reference standard
  • Maintenance factor and cleaning cycle made explicit
  • At least two alternative configurations documented
  • Verification protocol agreed before execution
  • Complete handover package (calculation, photometrics, maintenance plan)

Key takeaways

A motorway and major-artery 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

Why are motorways not lit end to end?+

Because continuous lighting is not always the most effective safety measure: standards and design practice concentrate it on interchanges, conflict areas, tunnels and sections with documented accident rates.

How is the transition between lit and dark sections handled?+

With a transition zone of decreasing luminance, allowing the driver's visual adaptation and avoiding the black-hole effect.

Where should a motorway and major-artery 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.