LandMeter

What 's Land Meter: landMeter is a utility app used in car to show the driver the slope and tilt of vehicle while driving on uneven roads, especially for off-road driving which the slope and tilt of road make driving harmful.

How to Use LandMeter: 

step 1: just put your iPhone on a holder as shown below 

step 2: rotate your iPhone into landscape mode.

step 3: launch the app and keep driving. you can see the real angle of your car in slope or tilt,