Billboard and Banner QR Codes: Resolution, DPI, and Viewing Distance Math

1. The Human and Optical Geometry of Billboard Scans

Placing QR codes on highway billboards or elevated building wraps requires calculating both viewing distance and the angular optical resolution of mobile telephoto lenses: $$ ext{Symbol Dimension} = rac{ ext{Distance}}{10}$$

If an elevated billboard is positioned 30 meters from pedestrians standing at an intersection: $$ ext{Minimum Symbol Width} = rac{30 ext{ meters}}{10} = 3.0 ext{ meters (approx. 10 feet)}$$

2. The Dangerous Fallacy of Highway Driver QR Codes

Safety Warning: Never place QR codes on highway billboards targeted at moving vehicular traffic. A vehicle traveling at 100 km/h (62 mph) moves approximately 28 meters per second. Attempting to locate, focus, and scan a QR code while driving introduces severe collision hazards. QR billboards should only be deployed in pedestrian-dense areas, transit waiting platforms, or static drive-thru lanes.