What Is Obtrusive Light and Why Is It Important?
Obtrusive light is artificial light that causes an unwanted or avoidable impact beyond the area it is intended...
We begin by reviewing the development proposals, external-lighting information, planning history and surrounding land uses.
The desktop review identifies potential receptors that may be affected by artificial light, including:
Nearby homes and other occupied buildings
Roads and transport infrastructure
Public spaces and neighbouring businesses
Habitats used by bats and other nocturnal species
Dark landscapes, rural areas and designated sites
Existing sources of external lighting
Aerial imagery, mapping, planning documents and available lighting information are used to establish the initial site context and assessment scope.
Where site-specific evidence is required, we carry out a night-time survey to record existing lighting conditions around the development site.
The survey may include:
Illuminance measurements at representative locations
Identification of existing light sources
Observations of glare, spill and sky glow
Review of neighbouring properties and sensitive receptors
Photographs and survey notes showing the existing night-time environment
The results provide a baseline against which the proposed lighting can be assessed.
We assess how proposed lighting could affect the surrounding environment and the people or wildlife using it. The assessment may consider:
Light spill beyond the application boundary
Glare experienced by residents, pedestrians or road users
Upward light and contribution to sky glow
Light intrusion at neighbouring windows
Effects on bats and other nocturnal species
Changes to dark corridors, habitats and landscape character
Effects on nearby businesses, public spaces and transport routes
Where an ecologist has identified sensitive habitats or species, we can use the relevant ecological information to assess the proposed lighting and recommend suitable controls.
Where the assessment identifies a potential effect, we provide practical recommendations that the lighting designer and wider project team can consider.
Recommendations may include changes to luminaire position, mounting height, beam direction, output, shielding, colour temperature, operating hours, dimming or automatic controls.
Send us the site details and proposed lighting information, and we will advise on the likely assessment scope, programme and fee.
A lighting impact assessment evaluates how existing or proposed artificial lighting may affect neighbouring properties, sensitive habitats, public spaces, road users and the wider night-time environment.
The assessment scope may include:
We prepare desktop assessments and site-based studies for exterior-lighting proposals and work with planning consultants, lighting designers, ecologists and environmental health officers throughout the planning process.
Each report identifies the guidance, planning context, assumptions and assessment criteria used for the project.
LED (Light Emitting Diode) – A semiconductor that emits light when powered. LEDs are efficient and long-lasting compared to traditional bulbs.
Light Pollution – Excessive or misdirected artificial light that disrupts natural darkness.
Sensitive Lighting Scheme – Lighting designed to reduce pollution, improve visibility, and suit its environment—balancing safety and ecological impact.
Glare – Harsh brightness that causes discomfort or impairs vision, typically from intense light sources contrasting with surroundings.
Colour Temperature – Measured in Kelvins; higher values mean cooler light; lower values mean warmer light.
Sky Glow – Night sky brightening overpopulated areas, caused by artificial light scattering in the atmosphere.
Lux (lx) – Unit measuring light intensity on a surface (illuminance).
Lumens (lm) – Unit measuring total visible light emitted by a source, regardless of direction.
Illuminance – The brightness of light reaching a surface, based on source intensity and coverage area.
Luminance – Light reflected or emitted from a surface, indicating its visible brightness, considering reflectivity.
Environmental Zones – Area classifications guiding lighting levels to reduce pollution and protect dark skies.
Obtrusive Light – Light spilling into unintended areas, often considered a nuisance depending on its intensity and surrounding light levels.
We provide a detailed Lighting Impact Assessment Report ready for submission with your planning application. This report includes:
The advancement of LED technology has significantly improved external lighting in recent years, offering brighter, more directional, and energy-efficient options compared to the older halogen lights. Additionally, LED lights tend to emit a whiter light, unlike their predecessors. However, despite the cost-efficiency of these new lights, improper design and placement can lead to negative consequences for humans, light-sensitive species, and the environment. Excessive light pollution, glare, and light intrusion can result if these factors aren’t properly addressed.
As a result, planning authorities now assess the potential impacts of existing or new lighting sources on surrounding areas. Their goal is to protect wildlife, prevent disturbances to people, and preserve the enjoyment of natural spaces and the night sky. If these factors are not considered during planning, a condition notice is typically issued.
No, it is not a general requirement. However, if you are in a dark skies area, such as a national park (e.g., the South Downs) or a rural countryside area, your local authority may require it.
Each local authority has its own approach to lighting, so it is advisable to check your local authority’s planning guidelines. Most authorities will require a Lighting Impact Assessment as part of their validation process if floodlights are being installed (e.g., on sports pitches or in industrial/commercial areas).
Addressing lighting considerations before submitting a planning application can help reduce delays and avoid the need for a condition notice.
Artificial lighting should be considered when a development is likely to increase lighting levels or when the development may be sensitive to existing lighting conditions. Although lighting offers benefits to society, it is crucial to ensure that the right type of light is used in the right location and at the time to maximise its effectiveness.
A lighting impact assessment evaluates how proposed or existing artificial lighting may affect neighbouring properties, road users, public spaces, sensitive habitats and the wider night-time environment.
An assessment may be required where a development introduces new external lighting, significantly changes existing lighting conditions or is close to homes, transport routes, ecological receptors or dark landscapes.
Lighting assessments may be needed for residential developments, commercial and industrial sites, car parks, sports facilities, schools, healthcare premises, roads, infrastructure projects and developments in rural or environmentally sensitive locations.
Useful information includes the site address, proposed lighting layout, luminaire details, mounting heights, operating hours, site plans and information about nearby properties, roads, habitats and designated areas.
Yes. Where site-specific evidence is required, Hawkins Environmental can carry out a night-time survey to record existing lighting conditions and identify nearby sensitive receptors.
The assessment may consider light spill, glare, upward light, sky glow, changes to existing darkness, effects on neighbouring windows, road safety, landscape character and potential impacts on bats or other nocturnal wildlife.
Yes. Where ecological receptors may be affected, the assessment can consider lighting near habitats, boundaries, trees, watercourses, bat routes and other areas used by nocturnal species.
Yes. Recommendations may include changing luminaire positions, mounting heights, beam angles, shielding, light output, colour temperature, operating hours, dimming arrangements or automatic controls.
Light spill is artificial light that falls outside the area it is intended to illuminate. It can affect nearby homes, roads, habitats and dark landscape areas if it is not controlled through careful design.
It is best to seek advice during the early design stage. Early input allows lighting layouts to be reviewed before they are fixed and can help avoid unnecessary glare, overspill, ecological effects or planning delays.
Obtrusive light is artificial light that causes an unwanted or avoidable impact beyond the area it is intended...
Lighting assessments are commonly required during the planning process where external lighting could affect neighbouring properties, transport infrastructure,...
Daylight and Sunlight Assessments can influence the design of a development long before a planning application is submitted....