Z-Maps Car
FAQ
Units without Play Services, speed differing from the car's dial, the '~ estimated' marker, and seven more.
Q&A
Frequently asked questions
My unit has no Google Play Services — can I install it?
Yes, and that is exactly the group the app targets. It uses plain LocationManager rather than Google's Fused Location.
Why does the app's speed differ from the car's speedometer?
Car speedometers are required to read a few percent high. The app derives speed from GPS, so it usually reads slightly lower and closer to true speed.
Why does the sign say '~ estimated'?
It means the limit was inferred by the app from road class and area, rather than read from map data. Public tiles carry no maxspeed tag, so most limits are of this kind.
Can it read engine RPM or coolant temperature?
No. The app does not connect to OBD-II and reads nothing from the ECU. Everything shown comes from GPS and the map.
Is there turn-by-turn navigation?
Not yet. V1 shows the map, your speed and the limit. Navigation is V2 and needs a separate routing engine.
Does it keep running while the reversing camera is on screen?
Yes. The driving loop lives in a foreground service, so the trip and the alerts continue while the app is hidden.
It reports the wrong limit on a road I drive every day. What now?
Correct it from the car. Open the limit editor, pick the right figure, and the app remembers it for the area around that spot and reuses it from then on. 'Use the default again' clears it.
Can I see my past journeys?
Yes. Trip history opens from Settings and shows total trips, total distance and total time, plus each journey with its average speed, maximum and overspeed count. Journeys under 300 m are not recorded.
How much storage does it use?
The APK is 10 to 44 MB depending on the build, plus up to 512 MB of map cache. The cache can be cleared from Settings.
Does the app collect data about me?
No. No account, and no journey is uploaded. Two things leave the device: map tile requests to OpenFreeMap, and an ad request to our server about once an hour — which carries no location, no journey and no device id.
So there are ads in it?
Yes, in one corner of the driving screen. They never cover the speed or the limit sign, and never interrupt a warning. Ads are chosen by slot rather than by you — there is no user profile and no third-party ad SDK in the app.
How do I advertise my own business in the app?
Register on the Advertise page. Individuals and companies both welcome. You pick a period and pay for the placement, and you get a daily delivery report when the campaign ends.