
Google has yet to release a stable build for Android Auto 15, but has already started rolling out Android Auto 15.1 beta. The update is coming a few days after the previous release to address issues, optimize performance, and prepare the app for upcoming additions.
Google has continued to support Android Auto with new updates every fortnight. The app has many inconsistencies, and these releases are supposed to address them. While they do just that most of the time, they also hint at upcoming features. Android Auto 15.1 does just that by suggesting that Material 3 Expressive Design will be coming to Android Auto soon.
Details of Android Auto 15.1 beta update

As usual, the update is limited to beta programs, but the APK file can be installed from the link below. It’s a normal update; it did not come with any user-facing changes. However, we understand there were some inconsistencies after the last release, and perhaps the need to release a new build to address all that.
The problem is with the Material You adoption. Dark background is missing for many people, while the interface does not look polished. These have now been resolved with refined Material 3 theme colors, making the toolbar color coordination more enhanced. Notification Panel, Head-up notification, Settings Interface, and third-party app interface all received some kind of optimization.
With the introduction of the Material 3 Expressive Design, Google plans to make further improvements. We expect to see vibrant, bolder color schemes with expanded palette options. Higher contrast ratios for improved readability while driving. Clearer visual separation between interactive elements and background content. Enhanced accessibility features for various lighting conditions.
Download Android 15.1 Beta update

Google is rolling out the update via the Play Store for beta testers. It has a version number v15.1.653404 and weighs about 32MB. Unfortunately, only select users can install the update from the Play Store, but you can side-load the APK file. If you are running Android 8 or later, you can download the file from this link.
We understand there have been cases where the app starts misbehaving after a new update. You should uninstall the update and move to an older build. Or wait for a stable release before jumping on that new release, since it doesn’t introduce many features. Perhaps you are having a hard time using the app after the last update, so you should install the new one.