Lighting design - DIALux road lighting simulation

Lighting needs to meet the following requirements:

* The recommended average illuminance (Lx) ensures that the road is bright enough to show objects;

* The recommended illuminance uniformity (Uo), which is the ratio of the minimum luminance to the average luminance in a specified area, ensures that no part of the road surface is too dark and the background of the object can be shown;

* The recommended longitudinal uniformity (Ul) refers to the ratio of the minimum luminance to the maximum luminance along the longitudinal line of the observer's position, which ensures that visible visual spots are avoided on the illuminated road surface;

* Blinding glare measured by the threshold increment of disabling glare (TI%) reduces the contrast between objects and their background. The recommended TI% limit ensures that glare does not impair the vision of road users.

 (2) Conflict areas (CE1 to CE5)

Conflict areas are areas of the road where traffic flows intersect and lane changes are frequent, such as bus stops, toll booths, parking lots, docks and intersections, pedestrian crossings, roundabouts, etc. The changes in the road layout or the heavy use of pedestrians, cyclists or other road users in these areas usually make the visual task more difficult than on a straight road. The main requirement of lighting is to provide a specific illuminance level and uniformity, and to adequately control glare. Lighting design is more suitable for using the illuminance method. The following are the lighting requirements for different conflicting areas:

(3) Sidewalks and bicycle lanes (no motor vehicle traffic, P1 to P6)

The lighting design of sidewalks and bicycle lanes is intended to provide a safe and comfortable environment for pedestrians and cyclists. Unlike highway users, pedestrians on sidewalks and non-motorized lanes need a brighter environment to feel safe. Therefore, the lighting of such areas is mainly based on the illumination level. For areas where face recognition is required (alleys), lamps with a color rendering index greater than 70 or higher should be selected, and requirements for the minimum vertical illumination level are also set. The following are the lighting requirements for different areas:

    ▪ Road Lighting Simulation Design Layout

Before conducting road lighting simulation, we need to make a detailed layout plan for the road, including the definition of street outlines and the arrangement of lamp poles.

(1) Definition of street outline

Street outline refers to the geometric shape of the road and the description of the surrounding environment. Its components vary depending on urban planning, traffic needs and regional cultural differences. In DIALux, we can define street outlines by importing CAD drawings of roads or drawing them manually. This includes information such as road width, number of lanes, sidewalk location, green belts, etc. Accurate street outline definition is the basis for accurate lighting simulation. Although there are significant differences in street layouts in different countries and cities, the core components usually include the following modules:

Motor vehicle lanes: the main space for vehicle traffic

Bicycle lanes: provide independent road rights for cyclists

Sidewalks: ensure pedestrian safety and walking experience

Parking strips: solve temporary parking or loading and unloading needs

Green belts: ecological isolation and landscaping

Central median strips: safe isolation of two-way traffic

Emergency lanes: used for emergency parking or rescue traffic

In specific planning practices, street outlines are often a flexible combination of the above elements. For example:

Simple roads may only have motor vehicle lanes;

Community roads often have a mixed layout of "motor vehicle lanes + bicycle lanes";

High-grade trunk roads need to be equipped with isolation islands and emergency lanes

 (2) Light pole layout

In road lighting design, the layout of light poles directly affects lighting uniformity, glare control, energy efficiency and project costs. We need to determine the location and spacing of light poles based on road type, lighting standards and lamp performance. In addition, the height and tilt angle of the light poles also need to be adjusted according to specific circumstances to ensure that the light can evenly cover the road surface. The following are 6 common road lighting pole layout methods and applicable scenario analysis:

1. Single-Side Arrangement

**Applicable scenarios**

- Road width ≤ 12m (such as branch roads, secondary trunk roads)

- Restricted space (such as under viaducts, narrow old urban areas)

**Layout parameters**

**Pros and Cons**

2. Staggered Arrangement

**Applicable scenarios**

- Road width 12~24m (main road, two-way four-lane)

- Scenarios that require a balance between illumination and energy saving

**Layout parameters**

      **Pros and Cons**

3. Opposite Arrangement

**Applicable scenarios**

- Road width ≥ 24m (expressway, two-way six-lane)

- Wider central isolation zone (> 3m)

     **Layout parameters**

**Pros and Cons**

**Optimization strategy**:

- Use high pole lighting (H≥15m) to reduce pole density

- Use asymmetric lighting fixtures to reduce glare

4. Central Median Arrangement

**Applicable scenarios**

- Urban main roads with central green belts

- Need to reduce glare to drivers

**Layout parameters**

**Pros and Cons**

5. Catenary Lighting

**Applicable scenarios**

- Narrow historical districts (no poles allowed)

- Bridges and tunnel entrances

**Layout parameters**

**Pros and Cons**

6. High Mast Lighting

**Applicable scenarios**

- Large interchange hubs

- Ports and airport aprons

**Layout parameters**

**Pros and Cons**

 (3) Recommended

Through DIALux simulation, the performance differences of different solutions can be quantified. It is recommended to give priority to:

1. Main road: staggered layout on both sides (best cost performance)

2. Branch road: single-side layout + wide light distribution lamps

3. Smart road: central isolation belt layout (easy to expand functions)

Note: The final solution needs to be optimized in combination with on-site surveying data (such as tree occlusion, underground pipelines), and CHZ can provide free simulation trial calculation services.

DIALux Road Lighting Simulation Design

After determining the lighting standards, street profiles and pole layout, we need to use lighting software. The street profile we mentioned now can be imported into DIALux, including the number of motor vehicle roads, sidewalks (bicycle lanes), medians, etc. Then, we can import the IES file of the lamps. Experienced designers can quickly select the appropriate street lights, power and spectrum based on the above information, and then adjust the design according to the needs.

 (1) Basic steps of Dialux road lighting simulation

1. Project creation and settings: Create a new project in DIALux and set the basic parameters of the project, such as geographical location, road type, lighting standards, etc;

2. Lamp selection and configuration: According to the road lighting requirements, select the appropriate lamp model and configure the lamp's light intensity distribution, power, color and other parameters in the software. We usually select high-performance LED lamps from the product library of CHZ Lighting Technology Co., Ltd. These lamps have high light efficiency, long life and good light intensity distribution characteristics;

3. Street profile import and editing: Import CAD drawings of roads or manually draw street profiles to ensure that the road geometry and surrounding environment are accurate;

4. Light pole layout and adjustment: Arrange light poles according to lighting standards and lamp performance. The position, spacing, height and tilt angle of light poles can be intuitively adjusted in the software to achieve the best lighting effect;

5. Simulation and evaluation: Run simulation to generate illuminance distribution diagrams, brightness distribution diagrams and glare evaluation diagrams for road lighting. Through these diagrams, we can intuitively evaluate whether the lighting effect meets the design standards. If it is found that the illumination in some areas is insufficient or the uniformity is not enough, the light pole layout or lamp parameters can be further adjusted;

6. Report generation and optimization: Generate a detailed lighting design report, including lighting parameters, lamp configuration, simulation results, etc. Based on the simulation results and customer feedback, optimize the design plan until a satisfactory lighting effect is achieved.

(2) Different street profiles in a project

In a large road lighting project, there are often many different street profiles. For example, a city's main traffic arteries may include highways, main roads, intersections, bus stops and other scenarios. In DIALux, we can create independent lighting schemes for each different street profile and manage and compare them uniformly in the same project. In this way, we can ensure that the lighting design style of the entire project is consistent while meeting the lighting needs of different areas.

(3) Scheme comparison

DIALux allows us to create multiple lighting schemes in the same project and compare them intuitively. This is very useful in actual projects because customers may have different preferences for different lighting effects. For example, we can create multiple schemes in a project: using different powers, different pole spacing and different lenses to import into DIALux software. By simulating and comparing the illumination distribution, energy consumption, service life and other parameters of these different schemes, we can show customers which of the different schemes is more suitable for the current road conditions, and continue to optimize other parameters to help customers make wise decisions.

For example, this illumination design upgrades the original 100W conventional street lamp to CHZ's new LED 100W street lamp ST29 series, achieving all-round optical performance improvement:

• Brightness is significantly enhanced

The average road illumination is increased from 13 lx to 22 lx (an increase of 69%), combined with the high light efficiency characteristics of LED (measured light efficiency> 150 lm/W), effectively expanding the lighting coverage and improving nighttime road visibility.

• Optimized glare control

The threshold increment (TI) is strictly controlled at 6%, and the key indicator of brightness uniformity - the glare value is optimized from 0.79 cd/m² to 1.31 cd/m², significantly reducing the risk of driver visual fatigue.

• Illumination uniformity upgrade

The road surface uniformity (U0) is increased from 0.55 to 0.58, and the bat-wing rectangular spot lens technology is used to eliminate dark areas and suppress light pollution, ensuring that light is accurately projected to the target area.

• Energy efficiency and reliability

At the same power consumption, the LED light source utilization rate is 3 times that of traditional sodium lamps, and the life span is extended to 50,000 hours, reducing maintenance costs; the mercury-free environmental protection characteristics are also in line with the requirements of sustainable development.

(4) Automatic optimization of lamp arrangement

DIALux provides an automatic optimization function for lamp arrangement, which greatly improves design efficiency. After setting the lighting standards and lamp parameters, the software can automatically calculate the optimal lamp pole spacing and position to ensure the best lighting effect. Of course, the results of automatic optimization still need to be manually adjusted and verified according to the actual situation to ensure the feasibility and economy of the design. The figure below shows how DIALUX realizes the automation of street lamp arrangement. You can see the appropriate lamp pole height. The optimized lamp pole spacing can be farther, which effectively saves costs.

CHZ Road Lighting Solutions

CHZ Lighting Technology Co., Ltd. is committed to providing customers with efficient, energy-saving and environmentally friendly road lighting solutions. Our products cover a variety of lighting equipment from LED street lights, tunnel lights to landscape lights. In road lighting design, we prefer to use our LED lamps because they have the following advantages:

1. High light efficiency: Our LED lamps have a light efficiency of up to 130-160 lm/W, which is 50%-70% energy-saving compared to traditional high-pressure sodium lamps.

2. Long life: The service life of LED lamps can reach more than 50,000 hours, reducing maintenance costs and replacement frequency.

3. Good light intensity distribution: Our lamps use advanced optical design to provide uniform illumination distribution to meet the lighting needs of different road types.

4. Intelligent control: Some LED lamps support intelligent control systems, which can automatically adjust the brightness according to traffic flow and ambient light intensity, further saving energy and improving lighting quality.

In actual projects, we provide customers with customized lighting solutions based on road types and lighting standards. For example, in a main road lighting project in a certain city, we used CHZ's LED street lights. Through DIALux simulation optimization, we achieved a good lighting effect with an average illumination of 30 lx and an illumination uniformity of 0.4, while saving 60% energy compared to traditional lighting solutions.

Conclusion

Road lighting design is a complex and important task that requires comprehensive consideration of multiple factors. Through this article, I hope everyone has a certain understanding of road lighting simulation and the application of DIALUX in lighting simulation. If you want to know more, you can also contact us. CHZ Lighting Technology Co., Ltd. can provide customers with efficient, professional and customized road lighting solutions. We strictly follow the lighting design standards, combine advanced LED lighting technology and intelligent control systems to ensure that each project can achieve the best lighting effect. In the future development, we will continue to be committed to technological innovation and product research and development, contribute more to the urban lighting industry, and illuminate every corner of the city with professionalism and quality.