Highway Light Poles: Heights, Spacing, Breakaway Bases and Fixtures for Motorways

Highways and motorways need light that is uniform over long distances, at high speeds, in all weather, from structures that are safe if a vehicle leaves the road. Highway poles are therefore taller, stronger and more carefully placed than street poles in towns. This guide covers the main design points.

When highways are lit

Not every highway is lit. Lighting is usually provided at:

• Interchanges, junctions and slip roads
• Toll plazas and service areas
• Urban motorways and ring roads
• Bridges and tunnels approaches
• Sections with high accident rates or frequent fog

Road authorities decide based on traffic, safety records and policy. Lighting classes come from standards such as EN 13201 or national equivalents; see road lighting classes.

Pole heights

Taller poles allow wider spacing and fewer poles, which reduces the number of obstacles beside the road. See how tall street lights are.

Layouts

Central median, twin arm: one row of poles in the central reserve, each with two arms lighting both carriageways. Efficient and common on dual carriageways with a wide enough median, usually behind a barrier.

Single-sided: poles on one side of the road with single arms, used on narrower roads.

Staggered: poles on alternate sides, for wider single carriageways.

Opposite: poles on both sides facing each other, for very wide roads.

High masts: at interchanges, a few tall masts light large areas from above, keeping poles away from the many ramps. See our high mast lighting guide.

Spacing

Spacing is typically about 3–4 times the mounting height, but the lighting calculation decides. For 12 m poles, that means roughly 35–50 m; with good asymmetric LED optics, more is often possible while meeting uniformity. The pole height and spacing calculator gives a first estimate.

Arms and outreach

Arms of 1.5–3 m bring the fixture over the carriageway. The outreach and fixture tilt affect the light distribution; LED fixtures with road optics are usually mounted level or with small tilt to limit glare.

Passive safety and breakaway bases

A rigid pole beside a high-speed road is a hazard. Options:

• Behind barriers: poles placed behind safety barriers or in protected medians
• Breakaway bases: slip bases or frangible couplings release the pole on impact
• Passive safety poles: designed to deform and absorb energy, classified under standards such as EN 12767
• Set back: poles placed outside the clear zone

The choice depends on speed, traffic, local rules and whether barriers are present. Wiring at breakaway poles needs disconnects so cables do not hold the pole after impact.

Structural design

Highway poles must resist:

• Design wind speeds for the location, often higher on exposed bridges and coasts
• The weight and wind area of fixtures and arms
• Vibration from traffic and wind, especially on bridges
• Fatigue at welds and base plates

Poles are usually hot-dip galvanised steel, tapered and designed by the manufacturer with calculations to local codes. Foundations are designed for the soil and loads. Our street light pole guide covers construction in more detail.

LED fixtures for highways

Requirements for highway fixtures:

• High system efficacy (130–170 lm/W) and road optics for wide carriageways
• Low glare, especially for high-speed traffic
• Surge protection of 10 kV or more, with extra protection in lightning-prone areas
• IP66 and IK08+ for exposure to spray and debris
• Dimming for low-traffic hours, and smart control for fault reporting
• Vibration resistance for bridges

Typical wattages are 100–250 W for continuous motorway lighting, depending on class, width and spacing. Our modular LED street lights are designed for main roads and highways. We supplied LED lighting for the Tanzhou Avenue expressway retrofit and the expressway toll station projects.

Maintenance

Maintenance on highways needs lane closures and traffic management, which are expensive. This makes long-life LED fixtures, reliable drivers and remote monitoring especially valuable. Smart control that reports failures lets crews fix several faults in one closure.

Retrofitting existing highway lighting

Many highways still have high pressure sodium lanterns. Converting to LED usually keeps the poles and arms, replacing only the lanterns, with savings of 50–70%. Check that the new fixture fits the arm tenon, that the light distribution suits the existing spacing, and that the poles are in good condition. See the HPS to LED conversion chart.

Solar on highways

Continuous highway lighting needs high output for many hours, which makes solar impractical on most main carriageways. Solar can suit lay-bys, rural junctions, signs and remote stretches. See advantages and disadvantages of solar street lights.

Glare and driver comfort at speed

At motorway speeds, drivers look far ahead and pass each light every second or two. Glare from poorly shielded fixtures, or a flicker effect from spacing and luminance patterns, causes fatigue. Highway lighting design therefore controls threshold increment (a measure of disability glare) and longitudinal uniformity along the lane, not just the average luminance. LED fixtures with well-designed road optics, mounted level, keep glare low while putting light where it is needed. When reviewing a lighting design, check that glare and uniformity values meet the class, and not only the average level.

Working with us

Send us the road cross-section, lighting class, pole height and spacing, and we will propose fixtures and IES files for a lighting calculation, and can supply poles and arms designed to your wind and safety requirements.