Z-Maps Car
Known limits
Where the app is weak, and what is deliberately out of scope — stated up front so you do not go looking.
Read this before trusting the number on the sign
With public map tiles, close to every speed limit is inferred by the app rather than read from data. The figure shown can be lower or higher than what is actually permitted. Road signs and traffic law are always the authority — the app assists a driver, it does not replace one.
Where it is weak
Stated plainly so you do not waste time thinking your unit is broken.
Stacked junctions
Where a flyover sits above a service road, road matching can lock onto the road underneath — distance and heading are nearly identical. There is a mild preference for bridge segments at speed, but this is a genuine weak point. When it happens, correcting the limit from the driving screen is the quickest fix.
Road matching depends on the rendered frame
The app can only recognise road segments that are actually being drawn. Normally that is fine because the camera follows the car, but if you pan the map away, matching pauses until the camera returns to the vehicle.
No navigation
The app does not do routing or turn-by-turn directions. That needs a separate routing engine — Valhalla or GraphHopper — which MapLibre does not include.
Very short journeys are not recorded
Trips under 300 m never reach the history. That is deliberate: reversing out of a parking space or shuffling a few metres would each create a trip, and a list full of those cannot be read.
Your limit corrections stay on this device
Figures you override are stored in a database on the device. Change head unit or uninstall and they are gone; there is no sync yet, and no way to share them with anyone else.
No engine data, and none is coming
The app does not connect to OBD-II, so there is no engine RPM, coolant temperature, engine load, battery voltage or DTC fault code. The only way to reach those without an adapter is Android Automotive OS on a manufacturer-built car, where engine RPM additionally requires a permission the carmaker grants — which does not apply to aftermarket head units, the app's main target.
These are being worked on
The roadmap says what comes first, and why.