Every line on the map is a real drive on a real road. Here's how we get from one to the other.
You don't have to take our word for it. This page is the audit trail — for residents who want to know if they can trust the green pill on their street, and for journalists who want to know what they can responsibly cite.
Phones do the listening, not the thinking.
Volunteer drivers opt into a passive mode in the RoadSense app. While they drive, their phone samples two things: how the car is shaking (accelerometer) and where it is (GPS). That's it — no microphone, no camera, no continuous tracking when stopped.
Anything that fails an on-device privacy filter never leaves the phone. Speeds below 25 km/h, idle moments at intersections, and any trace inside a user-set privacy zone (your home, your kid's school) are dropped before the upload step.
- 01Phone records
Accelerometer + GPS samples while driving. No mic, no camera.
- 02Phone filters
Anything below 25 km/h, idle, or inside a privacy zone is dropped on-device.
- 03Server matches
Clean traces are snapped to a road segment in OpenStreetMap.
- 04Public aggregate
Per-segment averages refresh nightly. No individual trace is ever published.
The map is built on the server, not on your phone.
When a phone uploads a clean trace, the server, not the phone, matches each drive sample to a road and turns repeated passes into public confidence tiers. It snaps the reading to a specific segment in OpenStreetMap, then averages it together with every other driver's readings on that same segment.
Doing this server-side is a deliberate choice. It means the math is consistent across app versions, and we can correct mismatches without shipping a mobile update.
Your phone never decides what your street looks like to the public. That decision is made by the average of many drivers on a shared map.
A green road isn't a promise. It's a confidence level.
Coverage is not the same as smoothness. A road can be well-driven and very rough; or sparsely driven and look smooth simply because not enough people have been on it yet.
That's why every published road carries a confidence tier. A "smooth" pill at low confidence is a hint. The same pill at high confidence is a claim.
A hint, not a claim. Treat the colour as provisional.
Pattern is real but the pill might shift as more data lands.
Stable enough to cite. Many drivers, many trips, agreement.
Stable beats real-time.
Data is refreshed in batches instead of pretending to be live. Aggregates recompute nightly. Tile caches refresh every fifteen minutes. A pothole reported at 2 PM today shows up on the public map tomorrow morning, after enough other drivers have hit it to confirm it's not a bag of mulch.
That delay is the price of a map that's worth trusting. We'd rather be a day late than a confident map of false positives.
What this isn't.
RoadSense is community observation. It's a way for people who use roads to describe their condition, in numbers, in public. To be clear about what it is not:
- Not a maintenance queue. A pothole on this map isn't a contract of repair. Municipalities pick their own priorities.
- Not a 911 substitute. If a road is dangerous right now, call your local public works line.
- Not surveillance. Individual driver traces are never published. Only the aggregate per road segment leaves our servers.
- Not a complete map. Roads with no driver coverage stay grey. Grey does not mean smooth.