Can I use the same LED luminaire for both city roads and highways?

The same physical fixture can sometimes be used with different secondary optic modules (beam angle inserts), but this requires a modular design. In practice, most manufacturers make separate models for highway (Type III/IV optic, higher wattage, IP66) and city roads (Type II optic, lower wattage, IP65). Using a city road fixture on a highway is a specification error that will fail the photometric compliance test.

How do I specify the correct optic type in a tender document?

Use the IES beam type classification: 'Type II' (narrow lateral, forward throw - for roads up to 8m width with single-side mounting). 'Type III' (medium lateral, forward throw - for roads 8–12m). 'Type IV' (wide lateral, forward throw - for roads above 12m). Alternatively, specify the required photometric performance directly: 'Luminaire shall achieve the maintained lux levels and uniformity specified in IS 1944/IRC SP-72 for the applicable road category, as demonstrated by a photometric report from a NABL-accredited lab.'

Does Xera Tech make different LED street lights for highways vs city roads?

Yes. Xera Tech's product range includes city-class (20–60W, Type II/III optics, IP65) and highway-class (60–150W, Type III/IV optics, IP66, 6kV surge protection) luminaires. Both ranges use die-cast aluminium housings and quality drivers. Contact connect@xeratech.in with your road classification for a product recommendation and photometric report.

Highway vs City Road LED Street Lights - Key Differences Explained

Beam Optics - The Most Critical Difference

City road (6–8m wide, 6m pole, single side): Type II asymmetric optic - projects light 60° forward along the road and 30° sideways. Low glare for pedestrians. Highway (10–14m wide, 10m pole, staggered): Type III or Type IV optic - wider lateral throw to cover the full carriageway width from a single side. Higher intensity forward throw for the longer spacing. Using a Type II optic on a highway leaves the far lane poorly lit. Using a Type IV optic on a narrow city road causes excessive glare to pedestrians and residents.

Wattage and Efficacy

City road 6m pole (6–8m wide road): 30–50W at 130+ lm/W achieves 10–15 lux maintained. Highway 10m pole (10–14m wide, 35m spacing): 80–120W at 140+ lm/W achieves 15–20 lux maintained. Higher wattage is needed on highways not just because of wider roads, but because: greater pole height means more lux loss (inverse square law). Wider spacing requires higher lumen output per fixture. Highway standards require higher uniformity ratio (Uo ≥ 0.40 vs 0.30 for city roads), which typically requires more fixtures or higher wattage.

Structural Specifications

City road pole: 6m, 3mm wall thickness GI, standard concrete foundation. Wind load design: IS 875 Part 3 basic wind speed for the city. Highway pole: 9–12m, 4–5mm wall thickness GI or heavier section, deeper foundation (IS 875 design wind speed for open terrain - typically higher than urban speed for the same location). Open highway terrain has no wind shelter from buildings - design wind speeds are 15–20% higher than urban. Highway poles must include anti-climb devices and high-visibility reflective bands as per NHAI guidelines.

Driver and Surge Protection

City road LED driver: 4kV/2kA surge protection minimum (IS 16102). Highway LED driver: 6kV/3kA surge protection minimum - open highway terrain is exposed to direct lightning. Highway luminaires also need: higher ingress protection (IP66 for highway wash spray vs IP65 for city roads). Better thermal management (mounted at greater height, reduced natural convection from vehicle movement at speed). NEMA or IK10 impact rating for vehicle debris impact. Anti-vibration mounting for vibration from high-speed heavy vehicles.