Google announced a major Android Auto redesign at I/O 2022. Codenamed 'Coolwalk,' it revamped Auto's UI for bigger infotainment displays and introduced a split-screen mode, among a barrage of other improvements. Eight months after the initial announcement and two months of beta testing, Google started rolling out the new Android Auto design for everyone at the beginning of 2023. The company has since then been spotted testing minor UI changes, though nothing major has rolled out. Google has now silently released Android Auto v10, with a new UI for Google Assistant.
With a big jump in version number, you'd expect the latest release of Android Auto to pack some new features or changes. But that is not the case. 9to5Google reports there is only one major change in Android Auto v10.0: a refreshed Google Assistant UI. However, whether the redesign is tied to the new build is unclear. It could be a server-side push from Google's side as well.
As for the new "glow" look, it is similar to how the voice assistant looks on Android smartphones with a bottom glowing bar. Google Assistant first appeared with this design on the Pixel 4 in October 2019. Before this new look, the voice assistant used to appear at the top of the screen of Android Auto with a black bar and an Assistant logo.
There does not seem to be any other immediate improvement associated with Google Assistant's new look on Android Auto, except for giving it a more modern look.
You can see if updating to Android Auto v10 triggers the new Google Assistant UI on your car's head unit, though your mileage may vary. Given how slow Google has traditionally been in rolling out Android Auto changes to everyone, do not expect the Android Auto v10 update to pop up on your phone anytime soon.