Determining the visibility of the outdoor LED display along roadsides and highways requires balancing pixel pitch, cabinet size, mounting height, brightness, content design, and structural safety to ensure users read your message at the correct distance and time. During the procurement process, you must answer two core questions: First, at what distance does the display need to be clearly visible? Second, how long does it take for viewers to see the message while moving? Once you understand these questions, you can select a pixel pitch, display physical size, and content layout that meet your readability and safety goals.
Pixel Pitch, Viewing Distance, and Resolution of Outdoor LED Display
When determining the size of an outdoor LED display, the first factors to consider are pixel pitch and viewing distance. Pixel pitch (P) is the center-to-center distance between LEDs.
JRVISUAL’s OFY Series Outdoor LED Display is an LED display solution suitable for digital outdoor advertising applications. Its pixel pitch and corresponding viewing distance are:
1. A 3.9mm pixel pitch has a recommended viewing distance of >3 meters.
2. A 6.25mm pixel pitch has a recommended viewing distance of >6 meters. 3. The recommended viewing distance for a pixel pitch of 7.81 mm is >8 meters.
4. The recommended viewing distance for a pixel pitch of 10.5 mm is >10 meters.
However, highway design must consider not only static resolution but also dwell time, the time it takes for drivers to read information. Traveling 100 meters at 100 km/h takes approximately 3.6 seconds. If you want drivers to be able to detect and read short headlines, the design should consider readability at the detection distance, plus an additional 3-5 seconds for reading the information. For example, if you want drivers to be able to read from 80 meters away, choose a pixel pitch with a D_min ≤ 80 meters. Many highways use a pixel pitch in the 8-16 mm range for larger displays.
Brightness, Contrast, and Viewing Angle of View for Outdoor LED Display
Selecting outdoor LED displays for roadside applications also requires specifying optical performance parameters to ensure readability in all daylight conditions. Therefore, the two most important optical specifications to determine are maximum brightness and contrast. For outdoor LED displays used for roadside digital signage facing sunlight, typical daytime peak luminance requirements range from 5,000 to 9,000 nits, depending on orientation and ambient conditions. Billboards facing highways typically require 5,000-6,500 nits to remain readable in direct sunlight without excessive blooming. In urban areas with strong reflections or high background brightness, brightness levels as high as 8,000-9,000 nits may be required.
High contrast comes from good LED modulation and optical design. Anti-reflective front modules and proper black level control improve perceived contrast in bright conditions. To ensure roadside readability, prioritize displays with high full-screen contrast at the measured ambient luminance.
Viewing angle is critical when drivers approach vehicles at an oblique angle (on a ramp or on a curved highway). LED modules typically offer a wide horizontal viewing angle (120°-160°). For roadside installations, ensure the beam pattern is centered on the main traffic flow and tilt the array or adjust the mounting angle to maximize the on-axis field of view for the majority of drivers. When mounting the display high above the road surface, consider the vertical viewing angle and ensure the LED lamps and lenses provide sufficient brightness at the expected approach angle.
Physical Dimensions, Cabinet Layout, and Safety Considerations
Once you have determined the pixel pitch and optical specifications, you need to determine the physical dimensions, cabinet layout, and structure of the outdoor LED display. JRVISUAL’s OFY Series Outdoor LED Display offers cabinet sizes such as 1000 × 1000 × 83 mm or 1000 × 750 mm modules, allowing you to assemble whole units to achieve the desired width and height.
For example, if using 1000mm-wide cabinets and the target display size is 6 meters wide x 3 meters high, six cabinets (1000mm wide) are required. If using 1000×1000 modules, six cabinets (6 meters wide) and three cabinets (3 meters high) are required. The total pixel size depends on the pixel pitch, as described above. For 1000×500 modules, you can stack 6×6 modules or mix custom sizes to achieve non-standard aspect ratios.
For roadside installations, front-maintainable modules are generally preferred, as rear access can be dangerous or impractical in roadside locations. The OFY Series Outdoor LED Display features a quick-lock system for fast installation with quick-release fasteners, and the cabinets are IP65+ rated.
Text Height, Viewing Time, and Content Strategies for Mobile Drivers
Even the best hardware system can be ineffective if the content design does not suit the habits of mobile viewers. Therefore, outdoor LED displays must present brief, high-contrast, and appropriately sized messages that drivers can read and understand within their limited viewing time. Traffic signage uses a 1-inch letter height for every 10 feet (≈25.4 mm/3.048 meters) of viewing distance. For example, at a viewing distance of 50 meters, the letter height should be approximately 417 mm. For highway applications, the target word count for key notifications is 1-7 words, and the exposure time for short marketing headlines is 3-6 seconds. Alternatively, for urban arterial roads with slower traffic, slightly longer messages can be displayed. Use high-contrast color combinations, minimize stroke width, and avoid thin serifs.
Deploying Visible, Safe, and Effective Roadside LED Billboards
Sizing outdoor LED displays for roadside and highway visibility requires determining target detection distance and dwell time, selecting a pixel pitch that meets viewing distance, and determining the physical screen size of the cabinet module to achieve the required visual coverage and resolution. Furthermore, determining peak brightness, contrast, and a high refresh rate to ensure sunlight readability and camera compatibility is crucial.
