In 2017, on a section of Autoroute 40 in Trois-Rivières. LED was common in general lighting by then but not yet established for highway application in Québec, and there was no reference design to work from. The photometric basis had to be built from the standard up.
Highway lighting in Québec at that point was still high-pressure sodium, and the design conventions around it had been settled for decades — known distributions, known spacings, known outcomes. LED changed every input at once. The distributions were different, the photometric files behaved differently at the spacings people were used to, and there was no completed provincial corridor to point at and say it worked there.
Which meant the usual shortcut was unavailable. Nothing could be adapted from a previous job, and no manufacturer layout could be accepted at face value, because there was no precedent to sanity-check it against.
The work began with the standard instead of a product. IES RP-8 designs roadway lighting on pavement luminance rather than illuminance, which changes the problem fundamentally: what matters is not how much light reaches the road but how much of it returns to a driver's eye, and that depends on the surface.
So the pavement classification came first — the reflectance characteristics of the surface, which determine how the luminaire's distribution translates into luminance the driver actually sees. Get that wrong and every downstream number is confidently incorrect.
Average pavement luminance, luminance uniformity and the veiling luminance ratio all had to be satisfied together, and on a highway the veiling ratio is usually what binds. It quantifies disability glare — stray light scattering inside the eye, washing out contrast at exactly the distances that matter at speed.
A layout can hit its average luminance target comfortably and still fail on veiling ratio, and it is not an intuitive failure to spot. It only appears when you calculate it, which is why the criterion has to be set before the geometry rather than checked after.
With the criteria fixed, the geometry followed from the photometry. Candela distributions were read from the manufacturers' IES files and tested against pole spacing, mounting height and setback — not a spacing chosen first and validated afterward, but spacing derived from what the distributions could actually hold across the span.
Pole positions and mounting heights were not inherited from an existing installation on this corridor, so the geometry was genuinely open. That made the exercise cleaner and also removed the excuse of working around constraints someone else had set.
The deliverable was the photometric calculation set: the pavement classification and its basis, the criteria each section was run against, the distributions selected and the spacing they supported, and the resulting luminance, uniformity and veiling luminance values. The design was reviewed and approved by MTQ engineers, and the ministry subsequently applied the same approach to another corridor — Route 335, on the Autoroute 19 extension between Autoroute 440 and Autoroute 640.
This work predates JGEC. It was carried out at the engineering firm where the principal was employed at the time, engaged as a subconsultant on the project, and the electrical engineering design and the professional seal were that firm's. The photometric calculation set described here was one part of that larger submission, produced early in a career with no prior roadway lighting experience — which is the reason it was done by reading the standard rather than by reaching for a precedent.
Because a driver sees the road surface, not the light falling on it. Luminance accounts for how the pavement reflects light back toward the eye, which depends on the surface classification and on the angle between the luminaire, the road and the observer. Two designs with identical illuminance can look very different from behind the wheel.
A measure of disability glare. Stray light scatters inside the eye and lays a veil over the retinal image, reducing the contrast available to detect an object on the road. RP-8 caps it as a ratio against average pavement luminance, and on high-speed roadways it is frequently the criterion that governs the layout.
It sets how the surface reflects. An asphalt surface and a concrete surface return light differently, and the classification drives the reflectance tables the calculation runs against. Assume the wrong one and the luminance results are wrong by a margin that no amount of care elsewhere recovers.
Yes. Roadway and site photometrics to RP-8, MTQ and MTO requirements, including the documentation package for the reviewing authority. Calculations are issued with the native AGi32 files.
A few lines is enough: the space, the levels it has to hit, and when it's needed. You get a written scope, a fee and a schedule back, normally within two business days.