What are the best practices for designing highway lighting systems to enhance safety?

1 Assess the needs and objectives

Before you start designing a highway lighting system, you need to assess the needs and objectives of the project. This involves considering factors such as the traffic volume, speed, and composition, the geometry and alignment of the road, the environmental and aesthetic impacts, the energy consumption and maintenance costs, and the legal and regulatory requirements. By defining the needs and objectives clearly, you can establish the criteria and performance indicators for the lighting system.

2 Choose the appropriate lighting levels and uniformity

The lighting levels and uniformity of a highway lighting system determine how well the drivers and pedestrians can see the road and its surroundings. The lighting levels depend on the luminance (the brightness of the road surface) and the illuminance (the amount of light falling on the road surface). The uniformity refers to the ratio of the minimum and maximum luminance or illuminance values. The appropriate lighting levels and uniformity vary depending on the type and function of the road, the traffic conditions, and the weather. You can use standards and guidelines, such as the AASHTO Roadway Lighting Design Guide, to help you choose the optimal lighting levels and uniformity for your project.

3 Select the suitable lighting sources and fixtures

The lighting sources and fixtures of a highway lighting system affect the quality, efficiency, and durability of the lighting. The lighting sources include different types of lamps, such as high-pressure sodium, metal halide, LED, and induction lamps. Each type has its own advantages and disadvantages in terms of color, life span, energy consumption, and environmental impact. The lighting fixtures include different types of luminaires, such as cobra head, shoebox, floodlight, and decorative luminaires. Each type has its own characteristics in terms of light distribution, glare control, mounting height, and aesthetic appeal. You can use software tools, such as AGi32 or DIALux, to help you select the suitable lighting sources and fixtures for your project.

4 Optimize the lighting layout and spacing

The lighting layout and spacing of a highway lighting system influence the effectiveness and efficiency of the lighting. The lighting layout refers to the arrangement and orientation of the luminaires along the road. The lighting spacing refers to the distance between the luminaires or between the luminaires and the road. The optimal lighting layout and spacing depend on the geometry and width of the road, the lighting levels and uniformity, the lighting sources and fixtures, and the visual comfort and safety of the users. You can use software tools, such as AGi32 or DIALux, to help you optimize the lighting layout and spacing for your project.

5 Integrate the lighting controls and sensors

The lighting controls and sensors of a highway lighting system enable the adjustment and monitoring of the lighting. The lighting controls include different types of devices, such as timers, dimmers, switches, and communication systems. The lighting sensors include different types of detectors, such as photocells, motion sensors, and traffic sensors. The integration of the lighting controls and sensors can help you achieve the following benefits: reduce the energy consumption and carbon emissions, extend the life span and reduce the maintenance costs, improve the adaptability and responsiveness, and enhance the safety and security of the lighting system.

6 Implement the lighting testing and evaluation

The lighting testing and evaluation of a highway lighting system involve the measurement and verification of the lighting performance and quality. The lighting testing includes different types of methods, such as photometric, electrical, and mechanical testing. The lighting evaluation includes different types of criteria, such as lighting levels and uniformity, color rendering and temperature, glare and flicker, and user satisfaction and feedback. The implementation of the lighting testing and evaluation can help you achieve the following goals: ensure the compliance and reliability, identify the problems and defects, improve the design and operation, and demonstrate the benefits and impacts of the lighting system.

7 Here’s what else to consider

This is a space to share examples, stories, or insights that don’t fit into any of the previous sections. What else would you like to add?