How Busy Is That Road Right Now? Count the Cars on Any California Traffic Camera, Free

Caltrans has thousands of traffic cameras watching California’s roads, and anyone can look at them. What nobody shows you is the number: how many cars actually went past in the last five minutes?

So I built a page that counts them, live.

Count the traffic →

How to use it

1. Open Passerby. It starts on Pacific Coast Highway at Crenshaw Blvd in Torrance.
2. Pick another camera: tap a quick pick (I-405 in Fountain Valley, or the busy intersections on PCH in the South Bay), search for a road or town, or click any amber dot on the map.
3. Watch. Every vehicle, cyclist and pedestrian gets a colored box, and each one is counted once when it crosses the dashed yellow line, in the direction it was going.

The cards under the video add it all up:

• Pedestrians, bicycles, motorcycles and vehicles, each split by direction
• An hourly rate once you’ve watched for a minute
• Counts per 1, 5 or 15 minutes, as a chart and a table, with a Download CSV button

Don’t like where the line is? Choose Top to bottom, or Draw your own with two clicks across just the lanes you care about.

Things worth trying

• Rush hour on the 405. Open 224 Magnolia around 5 pm and switch to 1-minute intervals. You’ll see the counts drop when traffic slows to a crawl: fewer cars pass a line when nobody is moving.
• Watch a traffic light work. On Manhattan Beach Blvd the cars queue at the red and then cross in a burst. The 1-minute chart looks like a heartbeat.
• Northbound against southbound. Many freeway cameras show both directions. Draw the line across all lanes and compare the two direction counts.
• Any YouTube video. Street cameras and city walks stream on YouTube from all over the world. Paste the link, share the tab when your browser asks, and the same counter runs on it (on a computer, in Chrome or Edge).
• Your own video. Press Try your own video and pick a clip from your phone: a street, a parking lot, a store entrance. It’s counted on your device and never uploaded.

How it works (the short version)

An object detection model (EfficientDet-Lite2, through Google’s MediaPipe) runs in your browser as WebAssembly. It looks at each video frame, in a few tiles around the counting line so that distant cars stay big enough to see, and returns a box for every car, truck, bus, motorcycle, bicycle and person. A small tracker links each box to the same vehicle in the next frame, and a vehicle is counted the moment its center crosses the line.

The model is about 12 MB and downloads once, from this site. The video comes straight from Caltrans to your browser, and nothing is sent anywhere else.

Honest limits

The counts are good estimates, not a traffic study:

• Distance. Highway cameras are high up and far away. A car at the far end of the picture is a few pixels tall, so draw the line where vehicles are bigger.
• Weather, glare and night all lower the count. So do heavy queues, where cars overlap.
• Cars and pickups get mixed up, so treat the split by type as rough. The total is the reliable number.
• Cameras move. Caltrans turns and zooms its cameras, and about one in four live streams was off the air when I checked. The page falls back to the camera’s still image and counts what’s in it.

Why I built it

Passerby is a working example of a footfall and traffic research tool: the same counting, pointed at a store entrance, a mall concourse or the street outside a billboard, tells a business how many people and cars actually pass. The Caltrans cameras are just the easiest way to show it working on real traffic, right now.

Want counts like these for your own location, or a tool like this on your own site? Tell me what you’d like to count.