To help emulate some of the configurations seen across OEMs, certain [hardware
profiles](https://developer.android.com/training/cars/testing/emulator#bundled-profiles) support runtime
configurability.

These configurations are implemented using [Runtime Resource
Overlays](https://source.android.com/docs/core/runtime/rros) (RROs)
and can be managed using the `adb shell cmd overlay` command.

Use the following commands to enable or disable a RRO:  

    adb shell cmd overlay enable <var translate="no">NAME</var>
    adb shell cmd overlay disable <var translate="no">NAME</var>

## Modify system bar position

By default, the configurable emulator has two system bars -- a status bar on the
top of the screen and a navigation bar at the bottom of the screen. Though many
cars share this layout, some don't. Of particular note is that some cars have
their system bar(s) on the horizontal sides of the screen and not the vertical
sides, which may break assumptions made when developing apps for mobile form
factors. See [System bars, immersive mode, and
edge-to-edge rendering](https://developer.android.com/training/cars/parked/automotive-os#bars-immersive-edge)
for more details and technical guidance.

The following RROs can be used to modify the system bars:

- `com.android.systemui.rro.bottom`
- `com.android.systemui.rro.bottom.rounded`
- `com.android.systemui.rro.left`
- `com.android.systemui.rro.right`

## Emulate display cutouts

Some cars have screens with display cutouts that are very different when
compared to those seen on mobile devices. Instead of the notches or pinhole
camera cutouts, some Android Automotive OS vehicles have curved screens that
make the screen non-rectangular. See [Adapt to irregularly shaped displays](https://developer.android.com/training/cars/parked/automotive-os#irregular-displays)
for more details and technical guidance.

The following RROs can be used to emulate display cutouts:

- `com.android.internal.display.cutout.emulation.top_and_right`
- `com.android.internal.display.cutout.emulation.free_form`
- `com.android.internal.emulation.automotive_ultrawide_cutout`

## Recommended testing configurations

Since the total number of configurations that can be created by combining these
RROs is quite large, we recommend testing your app using the following
combinations of [hardware profiles](https://developer.android.com/training/cars/testing/emulator#bundled-profiles)
and RROs, which are similar to some vehicles on the road today.

- *Automotive (1080p landscape)* with `com.android.systemui.rro.left` or `com.android.systemui.rro.right`
- *Automotive Ultrawide* with `com.android.systemui.rro.left` and `com.android.internal.emulation.automotive_ultrawide_cutout`