太陽光照明

都市道路照明の根底にあるロジック:光がどのように、なぜ、どこで照らされるのかを理解する

1. Introduction

Outdoor lighting design is a complex discipline that surpasses simple spatial illumination; it profoundly influences public safety, visual comfort, energy consumption, and the natural environment. Precisely controlling and distributing light is key to achieving these multifaceted goals. This article aims to provide a comprehensive analysis of key light distribution concepts—particularly cutoff fixtures (including full cutoff, cutoff, and semi-cutoff), non-cutoff fixtures, and batwing distributions—while strictly comparing them to established standards for street lighting in North America (primarily defined by the Illuminating Engineering Society of North America (IESNA)). By dissecting the technical definitions, characteristics, and typical applications of each type, this article will clarify the distinctions and synergies between them, offering valuable insights for professionals in urban planning, civil engineering, and lighting design to develop sustainable, compliant, and high-quality outdoor lighting solutions.

2. Understanding Cutoff Classification of Fixtures

The cutoff classification of fixtures defines the extent to which light is emitted above the horizontal plane, playing a crucial role in managing light pollution, glare, and light trespass. These classifications, historically defined by the Illuminating Engineering Society (IES), provide a framework for controlling upward light emissions.

2.1. Full Cutoff Fixtures

The light distribution of full cutoff fixtures is defined by two strict standards: first, the light intensity (candelas) at the nadir (directly below) at 90 degrees or above is zero, indicating that the fixture does not emit any light directly upwards 1. Second, the candela value at a vertical angle of 80 degrees or above per 1000 lumens of bare lamp does not exceed 100 (i.e., 10%) 1. These limits apply to all lateral angles around the fixture.

Full cutoff fixtures are designed to direct all light downward, thereby effectively minimizing skyglow (the brightening of the night sky) and light trespass (unwanted light spilling onto adjacent properties) 5. This characteristic makes them key to complying with dark sky regulations and preserving nighttime environments. Additionally, by strictly controlling high-angle light, they significantly reduce direct glare, enhancing visual comfort and safety for drivers and pedestrians 6. Their efficiency at precisely directing light only where illumination is needed also assists in energy conservation 6. Thus, many local regulations and environmental standards across North America mandate or strongly recommend the use of full cutoff fixtures 5.

Full cutoff fixture example

2.2. Cutoff Fixtures

The light distribution of cutoff fixtures is defined by specific candela limits: the candela value at a vertical angle of 90 degrees does not exceed 25 (2.5%) 2. At the nadir, the candela value at a vertical angle of 80 degrees does not exceed 100 (10%) 2. These limits apply to all lateral angles. While a small amount of light is allowed above 90 degrees, cutoff fixtures still significantly control upward light compared to semi-cutoff or non-cutoff fixtures, thereby assisting in reducing light pollution.

Cutoff fixture example

2.3. Semi-Cutoff Fixtures

Semi-cutoff fixtures have looser restrictions on upward light: the candela value at a vertical angle of 90 degrees does not exceed 50 (5%) 2. At 80 degrees, the candela value does not exceed 200 (20%) 2. These limits apply to all lateral angles. Compared to full cutoff or cutoff fixtures, semi-cutoff fixtures emit more light at high angles, increasing the potential for glare and skyglow. They are generally not recommended for environmentally sensitive areas or situations requiring strict control of light pollution.

Semi-cutoff fixture example

2.4. Non-Cutoff Fixtures

Non-cutoff fixtures are characterized by the absence of light intensity (candelas) restrictions above their maximum candela region 2. These fixtures emit light in all directions, including significant amounts directly upwards and horizontally. This lack of control leads to severe light pollution (skyglow), substantial light trespass into adjacent properties, and often produces uncomfortable glare 9. Due to growing environmental concerns and regulatory efforts to control light pollution, their use is increasingly restricted or prohibited in many jurisdictions 6.

Non-cutoff fixture example

The evolution from non-cutoff to full cutoff fixtures represents a thoughtful advancement in lighting engineering and regulatory framework aimed at mitigating the negative impacts of outdoor lighting. This trend emphasizes the growing importance of environmental responsibility and enhancement of visual quality in modern lighting design. Unrestricted light (characteristic of non-cutoff fixtures) leads to issues such as glare, light spillage onto adjacent properties, and widespread light pollution 9. Conversely, stricter cutoff classifications, like full cutoff, are engineered to address these issues, aiming to “reduce light pollution,” “minimize skyglow,” “reduce glare,” “enhance visual comfort,” and “increase energy efficiency” 5. This evolution in classification is a direct response from the industry and regulatory bodies (such as the International Dark-Sky Association and IES RP-33) to the recognition of light pollution and glare as significant issues, driving and establishing stricter standards to promote more responsible and sustainable lighting practices. It indicates that lighting design has shifted from merely providing illumination to offering “high-quality” lighting that considers its broader environmental and human impacts.

It is noteworthy that the traditional cutoff classification system is being replaced by the BUG (Backlight-Uplight-Glare) rating system 3. This transition marks a movement towards a more detailed, comprehensive, and actionable approach to assessing lighting performance, recognizing that uplight is only one component of light pollution and trespass. The traditional cutoff system primarily focuses on the emission of light at angles above 80° and 90° (uplight). However, the BUG rating divides spherical light distribution into three different zones: “Up,” “Front,” and “Back,” quantifying the amount of light in each zone 3. This means it evaluates not only uplight but also light spill to the back (backlight, leading to trespass) and glare (light emitting at high angles forward and potentially causing discomfort). This shift illustrates that controlling uplight, while important, is insufficient for achieving truly comprehensive and responsible outdoor lighting. Backlight can lead to significant light trespass onto nearby properties, and glare directly affects visual comfort and safety. The BUG rating offers a more comprehensive and nuanced framework for designers and regulators to address all major forms of light pollution and disturbances. This allows for more precise selection and design of fixtures, leading to better overall lighting quality, enhanced safety, and improved environmental management through a transition from a simple pass/fail system to a graded, multi-dimensional assessment.

Table 1: Comparison of Cutoff Fixture Classification Characteristics

Classification Type

Candela Limit at 90° (per 1000 bare lamp lumens)

Candela Limit at 80° (per 1000 bare lamp lumens)

Primary Features / Uplight Control

Relevant Impacts

Full Cutoff

0 1

Not exceeding 100 (10%) 1

Zero uplight

Excellent dark sky compliance, minimal glare, minimal light pollution

Cutoff

Not exceeding 25 (2.5%) 2

Not exceeding 100 (10%) 2

Very little uplight

Good glare control, reduced skyglow

Semi-Cutoff

Not exceeding 50 (5%) 2

Not exceeding 200 (20%) 2

Moderate uplight

Potential for glare and light trespass

Non-Cutoff

Unrestricted 2

Unrestricted 2

No uplight restrictions

High risk of light pollution and glare

3. Batwing Distribution

Batwing distribution represents a unique optical design strategy aimed at optimizing light quality and uniformity within the illuminated area. Unlike cutoff classifications that control uplight or the IESNA types that define the overall shape of light on surfaces, batwing distribution focuses on the uniformity of illumination.

3.1. Definition and Unique Profile

Batwing distribution is characterized by its ability to produce exceptionally uniform light output over a wide beam angle range 12. Its name “batwing” derives from the unique light intensity profile shape which resembles a bat’s wings when plotted on a polar graph, showing two peaks of intensity on either side of the nadir 12.

This unique distribution is typically achieved through the integration of specially designed diffusers or advanced optical elements within the fixture. These optical components work by breaking down the light emitted from LED sources into a series of small, evenly spaced beams. This engineered diffusion process transforms the more common “hotspot” distribution (where light is brightest in the center and fades quickly towards the edges) into a significantly more uniform light output 12. Additionally, some batwing designs utilize optical films to achieve “double-angle-bent light intensity” to meet specific illumination needs 13.

3.2. Advantages and Applications

Batwing distribution has several significant advantages over traditional light patterns:

  • More uniform light output: It ensures consistency in illumination levels across the entire beam angle range, minimizing changes in brightness and reducing the occurrence of dark spots 12.

  • Reduced hotspots: By eliminating concentrated areas of light, batwing distribution alleviates visual discomfort and creates a more aesthetically pleasing lighting environment 12.

  • Improved visual comfort and glare-free environment: The even distribution of light significantly reduces strong contrasts and direct glare, providing users with a more comfortable and ergonomic visual experience 12.

  • Increased productivity and mood: Studies show that comfortable, glare-free, and uniform lighting environments can positively influence user productivity and overall well-being across various settings such as offices, retail spaces, classrooms, and libraries 12.

Batwing distribution is an excellent choice for a wide range of applications requiring uniform, glare-free conditions:

  • Commercial and industrial spaces: Offices, retail environments, classrooms, and libraries benefit from shadow-free and hotspot-free lighting, enhancing focus and reducing eye strain 12.

  • Residential lighting: It helps create a more comfortable and warm atmosphere in homes.

  • Indirect lighting: Particularly effective when used with suspended indirect fixtures, light is directed to the ceiling to indirectly illuminate the space. This creates a broad, uniform pattern of reflected light, further enhancing uniformity and reducing direct glare 12.

Batwing distribution is an optical design feature that can be integrated into fixtures rather than being an independent classification system like cutoff or IESNA types. It addresses light quality and uniformity within the illuminated area, serving as a complementary function to broader classification systems. This distinction is crucial: batwing is not a replacement for IESNA or cutoff classifications but rather a sophisticated optical engineering solution that can be integrated into fixtures meeting specific cutoff and IESNA requirements. For example, a full cutoff fixture designed for a parking lot (e.g., IESNA Type V) may utilize batwing optical elements to ensure an evenly bright circular light pattern throughout the area without uncomfortable hotspots. This highlights that effective lighting design involves multiple overlapping considerations: controlling spill light (cutoff), shaping the illuminated area (IESNA), and optimizing light quality within that area (batwing).

The development and adoption of batwing distribution reflect a design philosophy that has transcended simply quantitative illumination (e.g., achieving a certain illuminance level), prioritizing qualitative aspects of lighting such as visual comfort and overall user experience. This marks a maturation of lighting design, where human factors are increasingly integrated into technical specifications. Traditional lighting design focused primarily on achieving minimum illuminance levels. However, “hotspots” and “glare” are recognized as issues leading to “discomfort and fatigue,” “visual strain,” and the creation of “uninviting” environments. The advantages of batwing (uniformity, glare reduction, enhanced productivity) directly address these qualitative deficiencies 12. This indicates a shift in priorities in lighting design. While meeting quantitative light levels remains important, there is a growing awareness that the “quality” of light distribution—how evenly and comfortably light is delivered—is equally vital for human well-being, task performance, and overall satisfaction in lighting spaces. This represents a more comprehensive, human-centered approach to lighting design.

4. North American Street Lighting Standards: IESNA Classifications

The Illuminating Engineering Society of North America (IESNA) has developed a fundamental classification system that prescribes how light is distributed on horizontal surfaces, which is critical for the design of roads, parking lots, and other outdoor areas across North America. This system provides a standardized language for describing fixture performance.

4.1. Overview of IESNA Classification System

The IESNA classification system is primarily based on the shape and extent of the lighting area produced by the fixture 8. It provides essential guidance for the design and installation of various outdoor lighting systems, including roads, sidewalks, and parking lots 8. The classification determines light distribution by measuring where most of the light falls on a standardized grid, emphasizing points of highest and 50% candela intensity (light intensity distribution). The system considers both lateral light distribution (across the road) and vertical light distribution (along the road direction) 8.

The comprehensive standard for lighting on roads and parking facilities in North America is ANSI/IES RP-8 (Recommended Practice for Roadway and Parking Facility Lighting). This document compiles numerous previous independent standards from IES and provides detailed guidance on design, maintenance, energy efficiency, environmental impact, and safety for various roadway and pedestrian applications 11.

4.2. Lateral Light Distribution Types (Type I, II, III, IV, V, VS)

These classifications define how light is laterally distributed along a road or lighting area, characterized by the point where the fixture reaches 50% of its light intensity 8.

  • Type I:

  • Characteristics: Provides a narrow symmetrical or asymmetrical elliptical light pattern, typically with a main beam angle of around 15 degrees. The 50% candela trajectory falls between one installation height (MH) on the house side and one installation height on the street side 8.

  • Applications: Most suitable for narrow, elongated areas such as sidewalks, narrow pathways, boundary lighting, and single-lane roads 8.

    Type I light distribution example
  • Type II:

  • Characteristics: Features a narrow asymmetrical pattern with a preferred lateral width of 25 degrees. The 50% candela trajectory falls between one installation height on the street side and 1.75 times the installation height 8. This type is usually suitable for fixtures located on the near side or nearby of relatively narrow roads where the width does not exceed 1.75 times the design installation height 9.

  • Applications: Suitable for 1-2 lane roads, major corridors, highways, wide sidewalks, small side streets, jogging paths, and bike lanes 8.

    Type II light distribution example
  • Type III:

  • Characteristics: Provides a wide asymmetrical pattern, preferably with a lateral width of 40 degrees, designed to project light outward and to the sides. The 50% candela trajectory falls between 1.75 times the installation height and 2.75 times the installation height 8. This type is typically mounted on the side of the area to be illuminated, where the width of the illuminated area should normally be less than 2.75 times the pole height 16.

  • Applications: Often used in major corridors, highways, parking lots, and large open areas requiring broader coverage 8.

    Type III light distribution example
  • Type IV:

  • Characteristics: Exhibits an asymmetrical forward-throw pattern, preferably with a lateral width of 60 degrees, providing strong and uniform lighting over a range from 90 to 270 degrees. The 50% candela trajectory falls between 2.75 times the installation height and 3.75 times the installation height 8. It emits an elliptical light pattern, directing more forward with a narrower width than Type III, making it highly effective in controlling light spillage 8. It is designed for mounting on the sides of wide roads, where the width does not exceed 3.7 times the installation height 9.

  • Applications: Best suited for peripheral applications requiring mounting on walls or poles, such as parking lots, plazas, and building exteriors, where light needs to be primarily directed forward and strict control over backward spillage is necessary 8. It emits light in a semi-circular pattern 21.

    Type IV light distribution example
  • Type V:

  • Characteristics: Produces a completely symmetrical circular light pattern with equal intensities at all lateral angles 4. The 50% candela trajectory is circularly symmetrical around the fixture 8.

  • Applications: Most suitable for illuminating large open areas from a central mounting point, such as parking lots, intersections, parks, and general work or task areas where light needs to be evenly projected in all directions 4.

    Type V light distribution example
  • Type VS:

  • Characteristics: Similar to Type V but produces a symmetric square light pattern with consistent intensities at all lateral angles 4.

  • Applications: Suitable for large areas requiring uniform square illumination, such as parking lots and public squares 9.

    Type VS light distribution example

Table 2: IESNA Lateral Light Distribution Types (I-V/VS)

IESNA Type

Half-Maximum Candela Point Range (in MH, street side/house side)

Preferred Lateral Width (degrees, where applicable)

General Light Distribution Pattern

Major Applications

Type I

1 MH on house side to 1 MH on street side 8

About 15 15

Narrow symmetrical or asymmetrical

Sidewalks, narrow paths, single-lane roads

Type II

1 MH street side to 1.75 MH 8

25 21

Narrow asymmetrical

1-2 lane roads, wide sidewalks, bike lanes

Type III

1.75 MH to 2.75 MH 8

40 16

Wide asymmetrical

Major corridors, highways, parking lots

Type IV

2.75 MH to 3.75 MH 8

60 9

Asymmetrical forward throw

Wall-mounted applications, parking lot peripheries, plazas

Type V

Circularly symmetrical around the fixture 8

No specific angle, 360° symmetrical 21

Circular symmetrical

Parking lots, intersections, large open areas

Type VS

Essentially the same across all lateral angles 14

No specific angle, 360° symmetrical 4

Square symmetrical

Large squares, parking lots

4.3. Vertical Light Distribution Types (Very Short, Short, Medium, Long, Very Long)

These classifications define how light is vertically distributed along the road based on the position of the maximum candela point 8. They are critical for determining appropriate pole spacing and ensuring uniform lighting along roadways.

  • Very Short (VS): Maximum candela point falls between 0 to 1.0 times the installation height along the road 8. Recommended pole spacing is approximately 1 times the installation height 14.

  • Short (S): Maximum candela point falls between 1.0 to 2.25 times the installation height along the road 8. Fixtures with “S” classification are generally suitable for situations where the pole spacing is less than 2.25 times the installation height 8.

  • Medium (M): Maximum candela point falls between 2.25 to 3.75 times the installation height 8. This type is suitable for situations where pole spacing is between 2.25 to 3.75 times the installation height 8.

  • Long (L): Maximum candela point falls between 3.75 to 6.0 times the installation height 8. Fixtures with “L” classification are suitable for larger pole spacing, specifically 3.75 to 6.0 times the installation height 8.

  • Very Long (VL): Maximum candela point falls beyond 6.0 times the installation height 8.

Table 3: IESNA Vertical Light Distribution Types (VS, S, M, L, VL)

IESNA Vertical Type

Maximum Candela Point Range (along the road direction in MH)

Recommended Pole Spacing (MH)

Major Applications/Implications

Very Short (VS)

0 – 1.0 8

1 14

Very small pole spacing

Short (S)

1.0 – 2.25 8

1.0 – 2.25 14

Smaller pole spacing

Medium (M)

2.25 – 3.75 8

2.25 – 3.75 14

Medium pole spacing

Long (L)

3.75 – 6.0 8

3.75 – 6.0 14

Larger pole spacing

Very Long (VL)

> 6.0 8

> 6.0

Very large pole spacing

IESNA lighting concepts overview

While the IESNA classifications are foundational, they serve more as guidelines rather than rigid rules. Their effective application requires consideration of numerous site-specific variables, underscoring the critical role of advanced lighting design tools and expert judgment in achieving optimal illumination. Several resources explicitly state that IESNA types are “guidelines” or “not fixed rules” and are influenced by factors like “fixture mounting height, tilt angle, arm length, and fixture-to-curb distance,” as well as “fixture layout and road conditions” 8. Documents also note the importance of “photometric data” and “modeling” in optimizing light distribution 15. The theoretical light distribution defined by IESNA types can change significantly due to specific installation parameters. For instance, incorrect mounting height or tilt angle may result in insufficient uniformity, excessive glare, or inefficient light distribution, even if the “correct” IESNA type is chosen. This complexity demands detailed photometric analysis and modeling, indicating that effective lighting design is an iterative and intricate process. It is not merely selecting a fixture type from a catalog. Designers must integrate theoretical knowledge (IESNA standards) with practical site conditions, validating their selections through advanced modeling tools. This emphasizes the value of expert lighting professionals in navigating these complexities to provide truly optimized and high-performance lighting solutions.

The IESNA system provides a solid framework for optimizing light coverage and pole spacing through its comprehensive classification of lateral and vertical light distribution. This dual classification directly contributes to improving energy efficiency and safety in roadway lighting projects. IESNA classifies light based on “lateral” (crossing the road, related to road width and coverage) and “vertical” (along the road direction, related to pole spacing) distribution 8. Lateral types (I-V/VS) match road widths (e.g., Type I for single lanes, Type II for double lanes, Type III for highways, Type V for large area lighting). Vertical types (S, M, L) correlate directly with “recommended pole spacing” and “pole height” 8. By precisely defining how light propagates laterally and vertically along the road, IESNA empowers designers to choose fixtures that minimize light overlap (wasting energy) and eliminate dark spots (affecting safety and visual comfort). For instance, opting for “long” vertical distribution can enable larger pole spacings, which can significantly reduce the number of poles and fixtures required for a given segment. This directly impacts initial installation costs and long-term energy consumption 8. Conversely, misjudging vertical distributions may lead to over-lighting or insufficient coverage between poles. The integration of lateral and vertical classifications allows for a highly optimized lighting design that is both functionally effective and resource-efficient. This optimization is crucial for achieving the goals outlined in standards like ANSI/IES RP-8-22, which include “minimizing energy use,” “enhancing driver visual quality,” and “providing high-quality light and increasing the visibility contrast of hazards” 18. It represents a systematic, scientific approach aimed at balancing lighting needs with economic feasibility, safety, and environmental impact.

5. Comparative Analysis and Design Considerations

Effective outdoor lighting design in North America reflects the complex interplay of various classification systems and optical characteristics. Understanding how cutoff fixtures, non-cutoff fixtures, batwing distributions, and IESNA classifications interact is crucial for developing optimal, compliant, and sustainable lighting solutions.

5.1. Interaction Between Cutoff Classifications and IESNA Types

Cutoff classifications (full cutoff, cutoff, semi-cutoff, non-cutoff) primarily control the amount of light emitted above the horizontal plane, serving as key mechanisms for controlling light pollution and glare 1. In contrast, IESNA types (I-V/VS) describe the shape and distribution of light on the ground, determining the effectiveness of illumination in areas such as roads or parking lots 8.

In contemporary North American street lighting, there is an overwhelming emphasis on using full cutoff fixtures. This preference is driven by stringent dark sky initiatives, environmental protection goals, and the desire to minimize light trespass and glare 5. These full cutoff fixtures are subsequently designed with specific IESNA lateral and vertical distributions (for example, full cutoff Type III medium distribution fixtures). The “cutoff” aspect ensures environmental responsibility by preventing light from spilling upwards, while the “IESNA type” ensures light is functionally directed and distributed to the target area (e.g., a multi-lane highway or large parking lot). These two systems work synergistically: cutoff addresses “where light should not go,” while IESNA addresses “where light should go and how it should be distributed.”

5.2. Integration of Batwing Distribution with IESNA Classifications

Batwing distribution itself is neither an IESNA classification nor a cutoff classification. Instead, it is a specialized optical design feature aimed at enhancing the “quality” and “uniformity” of light within the illuminated area 12. Its primary goal is to eliminate hotspots and provide a glare-free, comfortable lighting environment.

Batwing optical elements can be seamlessly integrated into fixtures with various IESNA distributions, particularly those designed for large-area coverage. For example, fixtures creating a symmetrical circular pattern (IESNA Type V) may be equipped with batwing optical elements 9. This combination creates a circular light pattern that is not only symmetrical but also exceptionally uniform without discomforting hotspots, making it highly suitable for areas requiring consistent lighting such as large plazas, central intersections, or open industrial spaces 9. Similarly, it may also be found in Type III distributions 23. This illustrates how batwing can serve as a qualitative enhancement within the quantitative framework of IESNA.

5.3. Comprehensive Considerations for North American Streetlight Projects

The selection of fixtures for streetlight projects in North America is a multidimensional optimization problem that necessitates a holistic approach balancing regulatory compliance (cutoff/BUG), functional requirements (IESNA lateral/vertical), and light quality (batwing, glare control), to achieve optimal safety, efficiency, and environmental management. This is seldom a singular, isolated choice.

  • Energy efficiency: Strategically selecting fixtures with appropriate cutoff classifications (especially full cutoff) and optimized IESNA types directly contributes to energy savings. By directing light precisely to the required areas and minimizing waste (uplight, backlight, spillover), overall energy consumption can be reduced 6. The widespread adoption of LED technology further enhances these efficiencies owing to its inherent design flexibility and higher lumen/watt output 9.

  • Visual comfort and safety: Minimizing glare and ensuring high illumination uniformity is crucial for visual comfort and safety. Proper cutoff fixtures can reduce discomfort glare for drivers and pedestrians, while appropriate IESNA types (potentially enhanced by batwing optical elements) ensure uniform light levels, reducing shadows and improving visibility of hazards 8. This directly correlates with reduced nighttime vehicle accident rates and increased pedestrian safety 18.

  • Dark sky initiatives and environmental impact: Adhering to full cutoff principles as well as guidelines from organizations like DarkSky International 7 and IES Recommended Practices (such as RP-33 Outdoor Environmental Lighting Recommended Practice) 5 is crucial for mitigating skyglow, protecting natural nightscapes, and preserving nocturnal ecosystems. This reflects a growing environmental awareness within lighting design.

  • Regulatory compliance: Local regulations, municipal codes, and state laws across North America often mandate specific cutoff classifications (e.g., full cutoff), and generally recommend or require various outdoor lighting applications to adhere to IESNA types 5. Compliance is not only a legal requirement but also a commitment to responsible urban development.

  • Economic benefits: In addition to environmental and safety advantages, optimized lighting design guided by IESNA standards and cutoff requirements can lead to significant economic benefits. This includes reduced initial installation costs (for example, by optimizing pole spacing with IESNA vertical types 8) as well as reduced long-term operating costs through energy savings 18. Moreover, well-lit areas can enhance public perceptions and potentially attract more foot traffic into commercial districts, boosting economic activity 18.

In practical applications, fixtures must meet multiple requirements: for example, they need to be “full cutoff” to comply with dark sky regulations and minimize light pollution 6; they must possess the appropriate IESNA lateral type (e.g., Type II or Type III) to effectively illuminate roads of specific widths 8; they should have the appropriate IESNA vertical type (e.g., medium or long) for optimal pole spacing along the road, ensuring uniformity and cost-effectiveness 8; and they might need to incorporate batwing optical elements to ensure surface light is evenly distributed without glare, enhancing visual comfort for users 12. Furthermore, all designs must comply with local municipal codes 5. This multifaceted requirement indicates that lighting designers cannot simply isolate one IESNA type. They have to consider the cutoff rating of the fixtures, their internal optical elements (such as batwing), and how these characteristics work together to meet the project’s various functional, environmental, regulatory, and aesthetic objectives. The complexity of finding fixtures that can simultaneously meet all these criteria often necessitates detailed photometric analysis and modeling tools 15. This highlights the critical role of expert consultation and comprehensive design processes in modern outdoor lighting.

6. Conclusion

Outdoor lighting design, particularly in North America, is a complex and nuanced field, centered on a profound understanding of various light distribution concepts. This article elucidates the fundamental distinctions between cutoff fixtures (full cutoff, cutoff, semi-cutoff), non-cutoff fixtures, and the specialized batwing distribution, providing a comprehensive comparison with the authoritative IESNA classification system for roadway lighting.

Cutoff classifications primarily serve as significant mechanisms for controlling light pollution and glare, where full cutoff fixtures represent the most stringent and environmentally friendly standards by directing all light downward. In contrast, non-cutoff fixtures significantly increase light trespass and skyglow due to the lack of such controls, resulting in their use becoming increasingly restricted. Batwing distribution differs from these broader classifications as it is an optical engineering solution focused on achieving exceptional uniformity and visual comfort within the illumination area, typically as a supplement to IESNA types for specific applications requiring hotspot-free lighting.

Ultimately, the best street lighting design in North America is a complex and comprehensive task. It requires integrating the precise, area-based distribution patterns specified by IESNA with strict cutoff requirements and, where appropriate, advanced optical solutions like batwing distribution. This integrated approach not only ensures functional lighting but also maximizes energy efficiency, enhances public safety and visual comfort, and maintains vital dark sky protection initiatives. Guiding the informed selection and professional design of fixtures under these integrated standards and considerations is crucial for creating sustainable, compliant, and high-quality outdoor lighting environments for communities.

ポータブルモバイルソーラーライトタワー

ハイブリッドエネルギーオプションを備えたLEDソーラー照明タワーの選び方

ハイブリッドエネルギーオプションを備えた適切なLEDソーラー照明タワーの選択

混合エネルギー源(太陽光、風力、ディーゼル、グリッド)を備えた太陽光照明タワーを選択するときは、照明の要件、範囲、機能性、実行時間、および特定の現場条件を考慮してください。

簡単な比較(初期スクリーニングによく使用される 3 つのモデル)

  • 小さな太陽タワー — 高さ: 6 m、照射範囲: 約 750 m²、光出力: 約 33,000 lm、バッテリーパック: 約 9.6 kWh、動作時間: 約 28.8 時間 (明るさによって異なります)。
  • 中型移動式照明トレーラー — 高さ: 9 m、照射範囲: 約 1,500 m²、光出力: 約 66,000 lm、バッテリーパック: 約 14.4 kWh、動作時間: 約 20 時間。
  • 大型ポータブル照明トレーラー — 高さ: 12 m、照射範囲: 約 2,200 m²、光出力: 約 198,000 lm、バッテリーパック: 約 28.8 kWh、動作時間: 約 20 時間。

注:実際の稼働時間は、明るさの設定、負荷、天候、設置場所の状況によって異なります。正確な計画を立てるには、実際のテストデータを使用してください。

ポータブルモバイルソーラーライトタワー

2. 照明範囲に基づいて選択する

小さな太陽タワー 6m(19フィート)で750㎡をカバーします。小規模なキャンプ場、道路整備地点、セキュリティチェックポイント、ゲート入口、信号所、個人作業エリアなどに最適です。より広い範囲をカバーする必要がある場合や、より高い高さが必要な場合は、下記の大型タワーをご検討ください。
中型移動式照明トレーラー (9 m / 29 フィート) は 1,500 m² をカバーします。建設現場、災害救助、鉱山地域などに最適です。
大型ポータブル照明トレーラー (12 m / 39 フィート) は 2,200 平方メートルをカバーします。大規模なイベント、主要な建設現場、災害対応、鉱山地域、軍事基地などに適しています。

3. 機能性で選ぶ

  • 4Gモニタリング: 人口密集地域、建設現場、機密性の高い場所でのリアルタイム監視が可能で、セキュリティと資産保護を強化します。
  • 緊急救助アプリケーション: ハイブリッド充電機能付きモデルを選択し、最大容量のユニットを優先して、災害対応のための稼働時間と明るさを最大限に高めます。
  • 電池のタイプ: 不安定な環境ではリチウムが火災の危険をもたらす屋外作業現場では、安全性を考慮して鉛蓄電池が一般的に選択されます。適切な安全対策を講じれば、LiFePO4 オプションも利用できます。
  • 5G基地局機能: 遠隔地や信号の弱い地域に役立ち、必要に応じて接続を拡張します。

4. 明るさとエネルギー効率

  • 明るさレベル 通常は 3 つの階層に分かれます。
    • 33,000 lm — 小規模な現場や低密度の作業区域に適しています。
    • 66,000 lm — 中規模の作業区域やセキュリティのニーズに適しています。
    • 198,000 lm — 高度なセキュリティ環境や広い視認性を必要とする大規模な運用に適しています。
  • 使用ガイド: 小規模なサイトでは、低めの明るさで十分な場合が多くありますが、大規模なサイトやセキュリティの高いサイトでは、高めの明るさが望ましいです。
  • エネルギー効率: 長期的な運用コストを削減するには、150 lm/W を超える照明器具の効率を優先します。

5. 色温度とレンダリング

  • 色温度の選択肢: 作業エリアや緊急作業の場合は 5000~6500 K (クールホワイト)、快適さが重要な休憩エリアや安全ゾーンの場合は 2700~3000 K (ウォームホワイト)。
  • 演色性(CRI): 高い CRI (> 80) は、緊急対応、採鉱、建設、キャンプ、安全チェックポイント、信号所、セキュリティゾーンなどの重要な環境で色と詳細を区別するのに役立ちます。
  • 効率: 効率の高い LED 照明器具は長期にわたってエネルギーを節約します。

環境への配慮とパフォーマンスのために、さまざまな条件下で照明を維持するために太陽光、風力、ディーゼル、グリッド電源を自動的に切り替えるハイブリッド エネルギー タワーを検討してください。

さまざまなハイブリッドエネルギーソーラー照明塔の理解

太陽光専用照明塔

ポータブルモバイルソーラーライトタワー

利点: 環境に優しく、運用コストが低く、メンテナンスが簡単。

  • 特徴: 360°回転と照明
  • 労働時間: 最大35時間

主な用途: 日当たりの良い地域、一時的または長期的な照明ニーズに適しています。

代表的なモデル:
ソーラー照明タワー(モバイル),
ソーラー照明タワー(バリエーション2).

風力と太陽光のハイブリッド照明塔

Sun+Wind ハイブリッド ソーラー トレーラーは、ソーラー パネルと風力タービンを組み合わせて、多用途のエネルギー ソリューションを実現します。このシステムは、さまざまな気象条件で信頼性の高い発電を保証するため、遠隔地に最適です。ハイブリッド アプローチにより、燃料への依存度が減り、運用コストが下がり、炭素排出量が減ることで環境への影響が最小限に抑えられます。持ち運び可能で簡単に設置できるこれらのトレーラーは、建設現場、イベント、緊急時の電力需要に最適です。

利点: 風の強い地域で安定した電力を供給します。

  • 特徴: 最大80時間の稼働時間
  • 主な用途: 遠隔地、風力資源が豊富な場所、災害後の非常照明

代表的なモデル:
太陽風ハイブリッドソーラータイター そして
サンウィンド モバイルソーラー発電機.

ディーゼル・太陽光ハイブリッド発電機タワー

Sun + Diesel ハイブリッド ソーラー テーラー

利点: 送電網にアクセスできない地域でも安定したエネルギーを供給できます。

  • 特徴: 最大80時間の稼働時間
  • 主な用途: 遠隔地建設、山岳救助、大規模イベントの物流拠点

代表モデル:
サンディーゼルハイブリッドソーラーテール.

グリッド電源照明塔

電動移動式照明塔

利点: 電力網が存在する場所では安定したエネルギー供給が可能です。

  • 効率: 195 lm/W 照明器具効率
  • 照明面積:1,200㎡
  • 労働時間: 35時間
  • 主な用途: 大規模建設現場、都市インフラ施設、イベント会場

代表モデル:
電動移動式照明塔(T300、6m).

クイックリファレンス選択表

モデル身長カバーエリア光出力バッテリー容量実行時間(標準)エネルギーオプション
小さな太陽タワー6メートル750㎡33,000ルーメン9.6kWh約28.8時間太陽光、ハイブリッド、ディーゼル、グリッド(オプション)
中型移動式軽トレーラー9メートル1,500㎡66,000ルーメン14.4kWh約20時間太陽光、ハイブリッド、ディーゼル、グリッド(オプション)
大型ポータブルライトトレーラー12メートル2,200㎡198,000ルーメン28.8kWh約20時間太陽光、ハイブリッド、ディーゼル、グリッド(オプション)

その他の考慮事項

メンテナンスとサービス

  • 照明器具と電池の定期点検
  • システム性能を維持するために太陽光発電パネルを清掃する
  • 定期的なチェックを通じてシステム全体の信頼性を確保する

環境適応性

  • 保護等級: 厳しい気象条件に耐えられるよう、高いIP等級(例:IP65)の器具を選択してください。

予算と総費用

  • 真の総所有コストを計算するには、機器の初期費用、設置、継続的なメンテナンスを考慮する必要があります。

ラックスマンのポータブルソーラー照明タワーは、高効率ソーラーパネル、長寿命リチウム電池、高輝度LED照明器具を採用し、長期にわたる安定した性能を実現します。また、ラックスマンは、多様な環境や要件に対応するため、ハイブリッドエネルギーモデル(太陽光+風力、太陽光+ディーゼルなど)も提供しています。

これらのガイドラインに従うことで、ニーズに最適な Luxman ポータブル ソーラー照明タワーを選択し、信頼性の高い照明と長期的なパフォーマンスを確保できます。

あなたのサイトに最適なモデルを見つける準備はできていますか? 今すぐラックスマンにお問い合わせください カスタマイズされたソリューションを提供します。

 

https://luxmanlight.com/street-light-distribution-analysis-how-to-meet-your-road-lighting-standards/

街路照明の配光分析 – 道路照明基準を満たす方法

これは、 道路灯のデザイン。

アイテム名ルートコード道路幅(メートル)表面タイプランプ構成ランプの数ランプの高さ(m)ランプ間隔(m)角度(°)ランプアームの長さ(m)ランプと道路間の距離(m)照度(1m)
ルート1M57メートルCIE C2(計算湿度)片側ランプ0.81240000.758000
ルート2M314メートルCIE C2(計算湿度)両側ランプ0.81040000.758000

さて、上記の条件に基づいて、ランプの配光を選択し、検証する必要があります。

まず、道路状況を分析しましょう。

国道1号線は、道路幅員7m、片側灯器配置、灯柱間隔40m、灯柱高さ7.5mの2車線道路とする。

国道2号線は、道路幅が14mで、双方向4車線道路とし、両側に灯器を配置し、ポール間隔を40m、ポール高さを9mとします。

これらの道路状況に基づいて、IESNA の街灯の分類を参考にして配光の選択を進めます。

IESNA街灯の分類

↑ IESNA街路灯の分類、北米照明マニュアル第10版

1車線から2車線の道路では、通常、タイプII街灯が選択されます。タイプIは歩道や歩道に適しており、タイプIIIは主要幹線道路に適用されます。

道路の幅に応じて以下のルールを参考にすることができます。

道路幅員配光誘導

上記の表によると、タイプII L配電を選択する必要があります。ただし、道路状況で規定されているランプと道路間の距離0.75mを考慮して、ポール間隔を若干調整し、タイプII MまたはS配電を選択します。

タイプII配光試験

DIALux evo で道路状況を設定して、ルート 1 のテストを始めましょう (DIALux4.13 は、新しい標準の選択に必要な EN13201:2015 標準をサポートしていないため、使用しません)。

DIALux evo ロードセッティング

ここでは、路面タイプとして CIE C2 を選択し、濡れた路面を計算するオプションをオンにして、W1 を選択する必要があります。

CIE C2表面はアスファルトに相当し、従来のR3の反射率に似ています。コードの詳細については以下をご覧ください。

CIE C2 表面タイプコード

道路状況を設定すると、検証計算用の配光を選択できます。

検証のためにタイプ II S 分布を選択します。

タイプII S配電構成

ランプ配置条件を設定し、ランプ光束を必要な5500lmに設定します。

ランプ構成設定

検証結果

タイプII S分布の検証結果

結果は満足できるものではなく、道路の輝度均一性は0.5cd/m²という基準値を下回っていました。しかし、UoとUow、そしてUlは基準値を大幅に上回っていました。

分布が少し不十分かもしれないという結論は出ましたが、具体的にどこが不足しているのでしょうか?輝度計算グリッドを分析する必要があります。

明るさ計算グリッド分析

上記の計算グリッドを分析した結果、2本のランプポール間の最小値が低いことがわかりました。これは、両端の配光を強化する必要があることを示しているため、計算ではタイプII M配光を直接選択します。

タイプII M配布への切り替え

タイプII Mの配布設定

検証結果

タイプII M分布の結果

結果はすべて満足のいくものであり、この配光は指定された 5500lm の光束の下で顧客の要件を満たすことができることを示しています。

次に、ルート 2 を見て、道路状況を 4 車線、双方向道路、M4 規格、計算された濡れた路面に設定してみましょう。

ルート2の条件設定

国道2号線の道路状況は、両側にランプが設置された4車線の双方向道路で、レベルが1段階向上していることを除けば、国道1号線とほぼ同じです。

配置には、再びタイプ II M 分布を選択します。

ルート2のタイプII M分布

検証結果

ルート2の検証結果

双方とも条件を満たしており、この配光は指定された6500lmの光束の下で顧客の要件を満たすことができることを示しています。

この分析から、配光を選択する際に従うべきパターンがあることが明らかになりました。 街路照明既存の製品を選択する場合でも、新しいディストリビューションを開発する場合でも、これらのルールに従って設計し、計算結果から欠陥を特定し、それに応じて適切な修正を行うことができます。

ラックスマン - 640 11

濡れた路面の輝度均一性を計算するのはなぜですか?

濡れた路面の輝度均一性を計算する必要があるのはなぜですか?

最近、クライアントから与えられた道路照明の要件に Uo の値が 2 つあるのはなぜかと尋ねられました。
実際、なぜ Uo 値が 2 つあるのでしょうか?
濡れた路面の輝度均一性を計算するのはなぜですか?
最もよく知られている道路照明の規格は、中国で広く使用されているCJJ45-2015「都市道路照明設計基準」です。この規格では、Uoは路面輝度の全体的な均一性を指します。
Uo参考画像
さらに、この規格には Uo 値が 1 つだけあります。
では、なぜ前述のクライアントのリクエストに 2 つの Uo 値が含まれているのでしょうか?
これが国際規格 CIE115/EN13201 につながります。
お客様から提供された要件では、道路区分はA1です。これは、適用される道路区分規格がEN13201-1:2004であることを示しています。DIALux 4.13をご利用いただいた方であれば、この規格についてよくご存知のはずです。
EN13201:2004 道路分類にのみ A1 レベルがあります。
EN13201 A1レベル分類
13201-1:2014 に到達すると、道路の分類は完全に変更されます。
道路分類の変更 EN13201-1:2014
13201-1:2014 に対応する照明規格は EN 13201-2:2003 であり、道路照明規格は次のとおりです。
道路照明規格 EN 13201-2:2003
ちょっと待ってください、全体輝度均一性Uoはまだ1つしかありません。では、もう1つのUoはどこにあるのでしょうか?ご安心ください。表をよく見ると、乾燥路面条件が指定されており、つまり濡れた路面の基準もあるということです。
乾燥路面と湿潤路面の路面基準
正解です。乾いた路面の標準レベルは ME ですが、濡れた路面の標準レベルは MEW です。ここで「W」は「濡れた」という意味です。
乾いた表面と濡れた表面の標準レベル
この表には、Uo 値が 2 つあります。1 つは乾燥条件での最小 Uo 値が 0.4 以上、もう 1 つは湿潤条件での最小 Uo 値が 0.15 以上です。
乾燥路面および濡れ路面状況におけるUo値
これはEN13201-2:2003規格に基づいているため、13201-2:2003の道路照明規格を統合したDIALux 4.13を使用して照度計算を行うことができます。2015年版を使用する場合は、DIALux evoが必要になります。
それでは、状況に応じてこの道路の照明を計算してみましょう。
道路照明計算の初期設定
クライアントの要件に応じて、英語インターフェースで新しい道路設計ケースを選択し、道路状況を設定します。
DIALuxの道路状況設定
道路状況を設定後、照明器具の配光分布を選択します。4車線双方向道路の幅員に基づき、タイプIII配光を優先し、ポール間隔とポール高さの比率に基づいてM配光またはS配光を選択します。
照明器具の測光分布の選択
↑このディストリビューションはDARKOO社提供で、ガラスレンズ素材を採用しています。
選択した照明器具分布ファイルのインポート
選択した照明器具の測光ファイルをインポートし、クライアントの要件に従って照明器具を配置します。
照明基準を設定し、標準値が要件と一致しているかどうかを確認します。
最適化条件を設定し、最適化を進めます。
DIALuxの最適化設定
最適化された結果表示
最適化の結果、1~2mのオーバーハングが要件を満たしていることがわかりました。ポールの材料を節約するため、最も短いオーバーハングを選択します。
結果をインポートし、最終的な結果を計算します。
照明計算の最終結果
これにより、クライアントの条件を満たす計算結果が得られ、レポートをエクスポートできるようになります。
ここで、国内の道路照明基準に濡れた路面に関する要件がないのはなぜかと疑問に思う方もいるかもしれません。濡れた路面を考慮した計算は必要でしょうか?
実際、「CJJ 45-2015 都市道路照明設計基準」では、「乾燥時の照度指標は湿潤時の照度指標と一致しない」と記載されています。例えば、全体的な明るさの均一性についてですが、乾燥時のUoが0.4の場合、湿潤時の0.2に到達するのは非常に困難です。しかし、湿潤路面における標準値は示されていません。
CIE115/EN13201における路面基準は、CIE 47-1979「濡れた路面における道路照明」に基づいて設定されています。この規格には、Rシリーズ4つ、Nシリーズ4つ、Cシリーズ2つ、Wシリーズ4つの表が含まれており、荒れた路面の輝度計算のニーズに対応しています。
しかし、これらの標準データ表のほとんどは、1960年代から1970年代にかけてヨーロッパの科学者が当時の典型的な道路材料について行った研究に由来しており、現在中国で広く使用されている道路材料とは大きく異なります。中国国内では道路材料の反射特性に関する研究が不足しているため、現在、中国には道路材料に関する標準的な反射率データが存在しません。そのため、中国の国内規格では、濡れた路面の照度基準は設定されていません。
もちろん、これは濡れた路面の照明インジケーターが重要でないという意味ではありません。実際、それは非常に重要です。
濡れた路面の照明の重要性
上の画像が示すように、最後の画像では濡れた路面の輝度均一性が乾いた路面の輝度均一性と大きく異なり、ドライバーに大きな影響を与えます。
雨の夜に運転したことがある人なら、雨の道路では視界が非常に悪いという経験をしたことがあるはずです。
雨天時の濡れた道路での視認性
したがって、濡れた路面状況における路面照明インジケーターの基準が必要です。