Having been announced in June last year, Google has today launched Android Auto with an app available on phones with Android 5.0. While a specific 'Android Car' is not available, your Android Auto app can be paired with a Pioneer head unit. As PC Pro points out "While they cost upwards of £700, you will get to use system straight away and it's cheaper than buying a totally new car. The choice is yours."
This is also true for Apple CarPlay, which can work with Pioneer too if you want to incorporate it into your current car. While Google may be building a legion of Android fans, with Apple CarPlay set to be fully integrated into a range of major auto brands we can't help but think that CarPlay may prove more popular. We can see that people may be swayed towards bolting an iPhone purchase onto their new Apple CarPlay-ready Ferrari rather than bothering with Pioneer to make Android Auto work.
One side note that must be added, is that while it appears that the fully integrated version of Apple CarPlay is available now from the advertised car manufacturers, that doesn't seem to be the case in practice. We called various car manufacturers including Audi, Range Rover, Infinity and Volvo to enquire about which models would come with Apple CarPlay. Disappointingly, only Volvo had any idea what we were talking about, but only to say that it will be available on the XC90 from November. Not the response we had hoped for.