How is a road or car park lighting design calculated?

By Gerard Bowtell-Harris, Technical Lighting Specialist, Raylinc Lighting

Every road, pathway or car park design starts with its lighting category, set by the council or road authority. The designer then maps the site’s critical points, places the first lights where the risk is highest, and builds the design out from there.

Start with the category and the site

Gerard Bowtell-Harris designs outdoor lighting for roads, pathways and car parks. Before he places a single fitting, he needs to know:

• The lighting category. The level the client and the governing authority have set for the space.
• The site’s pitfalls. Obstructions, nearby homes, and anything else that limits where light can go.
• The layout. Bends in the road, pedestrian crossings, and whether a pathway runs through an environmental zone.

Place the first light where the risk is

“The process begins with placing the first light wherever we have, say, a crossing that we need to manage or mitigate,” Gerard says. In a car park, the starting point might be the accessible parking spaces. The rest of the design builds out from those critical points.

Who sets the lighting category

The council sets it, or another governing authority such as Main Roads. “First and foremost, the council,” Gerard says. From there the category passes to the electrical engineer, who works with the client and the lighting designer to deliver it.

Where compliance gets hard

Gerard’s aim is simple: don’t put out a design that fails. The sticking point is usually existing infrastructure that can’t meet a newer standard or criteria.

There are three ways to close the gap: add a pole, use a different light, or step outside the standard. The last one rarely gets through. “Nine times out of 10, councils will say no, or the end client will say no,” Gerard says. The negotiation then comes down to an extra fitting or an extra pole.

Who is responsible for compliance

Responsibility usually sits with the lighting designer, the person who knows the lighting standards and categories. Some electrical engineers design lighting and know the standards well. Others rely on the lighting designer to bring that knowledge in.

The engineer still signs off the documentation for electrical compliance. “It’s a bit of a joint process,” Gerard says. “Whoever’s completing the design, realistically, the responsibility’s on them in terms of the compliance.” Everyone else along the way holds the designer to account.

Frequently asked questions

Who decides the lighting category for a road or pathway?

The council or governing authority, such as Main Roads. The electrical engineer and lighting designer then design to that category.

Which standards cover road and pathway lighting in Australia?

The AS/NZS 1158 series, Lighting for roads and public spaces. AS/NZS 1158.3.1 covers pedestrian area (Category P) lighting, and AS/NZS 1158.1.1 covers vehicular traffic (Category V) lighting.

What happens when existing poles can’t meet the standard?

The usual fix is an extra pole or a different fitting. Councils and clients rarely accept a design that steps outside the standard.

Who is responsible for compliance on a public lighting scheme?

The lighting designer carries responsibility for design compliance. The electrical engineer signs off the documentation for electrical compliance.

Gerard Bowtell-Harris is a technical lighting specialist at Raylinc Lighting and a member of the Illuminating Engineering Society. He designs lighting for roads, pathways, car parks and facades with consulting engineers.

Contact the Raylinc team to start an outdoor lighting design for your next project.