How to Use the Phase Calculator
Step-by-step guide to the free Phase Calculator tool. Upload a CSV of times and locations. Get back the sun's exact position and whether streetlights were on, for every row.
After Dark: A Year of Road Crashes, Mapped by Twilight Phase
An interactive map of 8,293 road crashes in 2024, each classified by the calculated position of the sun. Darkness is 31% of crashes but 42% of the deaths — a crash after dark is 1.6× more likely to be fatal.
How Street Lighting's Lowest-Liability Guesses Result in Overlighting
Street lighting design assumptions aren't best guesses, they're lowest-liability guesses, and every one biases toward more light. Five stacking factors add up to 50 to 150 percent overlight on every street.
Calculating the Value of Street Light Optimization for Transportation Safety (2 of 7)
Street lighting optimization reduces crash-related municipal costs by $7.82 per light per year. Original FARS analysis shows fatal crashes spike at the darkness transition. BCA of 1.56 on transportation safety alone.
LED Conversion vs. Optimization: Comparing the ROI
LED retrofits saved energy but left the same crude design in place. Per-luminaire optimization cuts another 25–50% from systems that already converted.
Calculating the Value of Street Light Optimization for Utilities (1 of 7)
Using California's Avoided Cost Calculator, we show that each optimized streetlight generates $10.18 in annual utility cost avoidance — $203,699 for a fleet of 20,000.
The LED conversion is over. What comes next?
LED-to-LED swaps don't pay for themselves. The next value in street lighting is software that optimizes how installed lights operate.
Why Adaptive Street Lighting Is the Next Infrastructure Priority
Most adaptive lighting is just blanket dimming with a network connection. Real optimization calculates every luminaire individually using GIS and photometric data.