How to count trailers in warehouse yards from above
Search aerial imagery for "trailer" over the yards you care about, and a detection model outlines and counts each one it can see. Over about 0.4 square miles of Fontana, California, one search counted 174 trailers. The count describes the day of the picture, not how busy the yards are.
To count trailers in warehouse yards from above, search aerial imagery for "trailer" over the yards you care about, and a detection model outlines and counts each trailer it can see. When we did this over about 0.4 square miles of warehouse yards in Fontana, California, in September 2026, one search counted 174 trailers in a single picture. The count describes the day the picture was taken. It does not measure how busy the yards are.
That makes a trailer count useful for comparing sites and asking better questions, and not useful as a measure of throughput, vacancy or a tenant's health.
What we found in Fontana, California
One plain-word search, "trailer", over about 0.4 square miles of warehouse yards, run on 23 September 2026, outlined 174 trailers. Each trailer is drawn on the map, so you can see which yard holds them and how they are parked, not just the total.
A search of that size is quick. Across 50 of our own scans of about 0.4 square miles each, the median took 49 seconds.
How the count works
You describe what to count in plain words. Our detection model reads the search as written, outlines each match it finds in Mapbox satellite imagery and counts them. The same search works for trucks and shipping containers in a yard or terminal. We did not check every outline in Fontana by hand.
The included imagery shows detail to about half a metre per pixel, which is enough to see a trailer. Trailers parked tight together, backed into dock doors or in shadow can be harder to separate, so treat any count as close rather than exact.
What a trailer count cannot tell you
- Activity over time. A count is one picture. The same yards on another day, or at another hour, could hold far more or far fewer trailers.
- Today's yard. The included imagery can be months to about two years old depending on the place. Every result shows its date. A fresh capture can be bought separately when you need a current view.
- Throughput, vacancy or tenant health. A full yard can mean a busy site or a backlog. An empty one can mean a quiet day. Ask the operator before drawing a conclusion.
- Loaded or empty. A trailer from above looks the same either way.
For sites you watch, we check every six hours for a clear new picture, screened for cloud over the site itself, and flag when it looks different from the last clear one. We do not recount trailers automatically on each new picture; run the search again when you want a new count.
How to use a count in a site decision
- Draw the yards you want to compare and run the same search on each, so the counts are like for like.
- Compare counts from pictures taken on similar dates. Note the date with every number you report.
- Look at the layout as well as the total: how much yard there is, how the trailers are parked, and what is around the site, such as rail lines and highways.
- Where a US county or state publishes parcel ownership as public record, see the owner on record for each site, and check the zoning district in about 55 of the largest US cities. Confirm zoning with the local authority.
- Model a site you are serious about with a pro forma in Financials, and take the questions the count raised to the operator or broker.
Pro is $49 a month for one person and covers up to 100 square miles of search a month. See how logistics teams use the same tools on our logistics page, or book a demo and bring the yards you want to compare.
Related guides
- Warehouse yard activity from satellite imagery
- How to monitor remote properties with satellite imagery
- How many parking lots in a market need resurfacing
Key takeaways
- One plain-word search over about 0.4 square miles of Fontana yards counted 174 trailers.
- A trailer count describes the day of the picture, not throughput, vacancy or tenant health.
- Compare sites with the same search on pictures from similar dates, and report the date.
- Run the search again for a new count; it is not repeated automatically on new pictures.