From an App Developer’s View: Android Auto vs. Apple CarPlay vs. MirrorLink

Have you been thinking of enabling your mobile app for safe use inside a car while driving? To overcome the discrepancy between the need of constant communication and the restriction of handling a mobile device by a driver, various automotive and mobile device manufacturers have developed several approaches to enable the safe use of modern communication devices while driving. Traditionally this can be achieved by the use of the Bluetooth Hands Free Profile (HFP), but this is restricted to classical phone-calls. For modern smartphone applications this might not be sufficient. In this post we are going to explore the three major approaches of using an app without distraction from safe driving.

The Candidates

There are three very interesting specifications around, each of which has a lot of backing form major players of the automotive and the digital industries:

• The Open Automotive Alliance (OAA) led by Google published Android Auto with the latest Android releases. It is currently available only for selected regions of the globe, but more regions are to follow soon.
• MirrorLink was originally designed by Nokia in 2011, but is now maintained and published by the Car Connectivity Consortium, which unites car and phone manufacturers covering according to self-statements some 70-80% share of the total market.
• Apple introduced CarPlay with the release of iOS 7.1.

All three protocols require a modern mobile device (smartphone) with a recent release of its operating system as well. For Android Auto the mobile device is required to run Android 5.0 Lollipop (or newer) and needs to have the Android Auto App installed; For CarPlay an iPhone 5 (or newer) is required. Mirror Link is independent of the operation system, but a MirrorLink server software is required, which is usually provided by the mobile device manufacturer as OS extension or app. Currently HTC, Sony and Samsung have certified their recent devices to support MirrorLink. All three protocols are supported by several car manufacturers. Most car manufacturers support multiple protocols and have not restricted their commitment to a specific protocol.

App Possibilties and Limitations

The main difference between the three protocols are the possibilities and limitations of an app. In MirrorLink the app is granted control of the entire head unit display, so the app has the possibilty of sending any information to the screen. In contrast, Android Auto only allows apps that play audio media and implement messaging services and do not take control of the entire screen, but just provide the content. In this context, CarPlay is similar to Android Auto, but not so clearly restricted to those two app classes. Therefore it is – for example – not possible to write an app, that provides an alternative navigation system, as Google and Apple would only allow their native navigation solutions (i.e Google Maps or Apple Maps resp.) to be part of the solution, while MirrorLink is more open.

On the other hand, Android Auto and CarPlay have integrated voice recognition. Concerning driver safety, this allows a simpler implementation of messaging service apps, while a messaging service app in MirrorLink would need to implement voice recognition by itself. All three protocols allow the use of vehicle data, such as the current speed, for in-app use. Also, all three protocols require an app to be controllable via rotary knobs instead of the touchscreen.

Also with all three approaches, app developers have to tightly follow the protocol publishers› guidelines to ensure all safety-related issues are resolved and do not pose a risk to driver safety. Therefore all three publishers have installed app certification / approval processes in their protocols. In MirrorLink an app is either certified for «parked mode» only or also for «driving mode». Obviously «drive mode»-certification has higher requirements concerning driver safety than a simple «parked mode»-certification.

Outlook and Conclusion

Another point of interest is certainly the future development of the three protocols, as not all developers have the resources to maintain their apps for all three protocols. Currently no statement is possible yet, whether Android Auto, MirrorLink or CarPlay emerges as «the» standard for car infotainment connectivity. Therefore it is adivisable to further observe the development and discussion.

In the current situation, one can conclude, that MirrorLink offers most possibilities as the app can take control of the entire screen, but this comes at the price of the required app certification process and the required support by each mobile device developer. Contrary, Android Auto and CarPlay are part of the operating system and therefore independent of the mobile device manufacturer.

Update 2017-07-02: Also read our follow-up post for more information what happend since this post has originally been published: https://www.noser.com/techblog/car-connectivity-revisted/