Slow Them Down

Slow Them Down turns your iPhone into a traffic speed study tool. Record vehicles on your street, mark their positions frame by frame, and get accurate speed estimates — no radar gun required.

How it works

1. Calibrate your camera using a known reference distance (vehicle length, lane width, or a manual measurement)
2. Record a video of passing traffic
3. Select two frames and mark the vehicle's position in each
4. Get an instant speed estimate in MPH

Track every vehicle Log each measurement with vehicle type, travel direction, street name, and timestamp. Build a complete picture of traffic patterns in your neighborhood over days, weeks, or months.

Automated reports Generate detailed PDF reports with V85 speeds, traffic volume breakdowns, speed distribution charts, and vehicle type summaries. Filter by street to isolate problem areas. Share reports directly with your city council, HOA, or neighborhood group.

Privacy built in Faces and license plates are automatically detected and blurred before you share anything. The app errs on the side of caution because a blurred street sign is better than a visible plate. We also don't store the images, videos beyond the processing needed to calculate a speed.

Built for advocacy Speed data is what cities use to justify traffic calming measures like speed bumps, stop signs, and road diets. Slow Them Down gives your community the same data, collected from the streets you actually live on.