Editor's note, December 24, 2014: This article has been updated to reflect further information about Android Auto.
As a CNET reader with a healthy addiction to technology, you likely already know why a phone and the apps it's powered by can be useful in the car. Your phone is a hub for your audio and entertainment, GPS navigation, and communications with your friends, family, and social circles. You've got your apps for streaming music and podcasts from the Web, apps for picking a place to eat or finding the lowest fuel prices around, and your hands-free calls of course. Or, because phones are such personal devices, your handset may bring only a few of these things to your driving experience.
You're in charge of why you'd want to use your Android phone in the car. The tricky part is figuring out how to do it and how to do it safely. Read on.
Tried, true: The analog auxiliary input
For drivers of older cars or vehicles with more basic car stereos, the humble analog auxiliary audio input (3.5mm TRS) is the next best bet. You'll connect to this simple audio connection with an audio patch cable that plugs into your phone's headphone jack.
The auxiliary input's simplicity makes it the easiest to set up and, possibly, the most future-proof of phone-to-car connection methods. However, this connection is a dumb input, lacking bidirectional communication, so there's no way to control your phone with the car's stereo. If you want to, for example, change songs, then you'll need to interact with your Android phone, which can be less than ideal in a driving situation.
Your best bet: Bluetooth
For most of the Android operating system's lifetime, Bluetooth's Advanced Audio Distribution Profile (A2DP) has easily been your best bet for piping audio from an Android phone through the speakers of most newer-model vehicles. This is especially true if you're already making the Bluetooth wireless connection for the Hands-free Profile (HFP) for voice calls -- using A2DP kills two birds with one stone. Bluetooth A2DP will send any audio that your phone outputs wirelessly, including turn-by-turn directions, if you happen to be navigating. More often than not, A2DP-connected stereos will also display artist and title data for the currently playing song and almost always include shortcuts (either onscreen or accessible by steering-wheel buttons) for Play, Pause, and Skip.
Bluetooth-to-stereo audio streaming does have one minor drawback. When you make the wireless connection, your phone and the receiver must negotiate the audio quality at which the music will be streamed. While there is startlingly little information published about how this process works and what specific bit rates and compression algorithms are used, suffice it to say that the audio quality is always less than audiophile-level. What's more, some phones sound better than others, even within the same brand, and there's no guarantee that a phone that sounds good with a Honda stereo will sound just as good with a BMW's, for example.
Fortunately, the audio quality that I've observed when Bluetooth streaming has improved significantly over the last few years. With all but the top-tier premium audio systems, most listeners probably won't notice, but for those connecting older phones or older stereos, it bears mentioning.
If your car stereo and phone both support pairing for audio streaming, then it should happen automatically when you pair for hands-free calling. Pop into your phone's Wireless settings and locate the Bluetooth menu. Make sure that your phone's Bluetooth is set to On and, following the instructions that came with your car, place the car stereo into its pairing mode.
Tap the "Search for devices" button in your phone's Bluetooth menu and look for your car's ID to appear. It should say something like "Elantra," "NISSAN," or "MYCAR." Tap the ID and, if prompted, enter the PIN that may be given to you by your car stereo. Sometimes you'll be asked to confirm the connection and sometimes the pairing will just happen automatically. You should only have to pair your phone with your car once, with subsequent reconnections happening automatically.
At this point, you'll usually be asked to sync your phone's address book. This is usually a good idea, so be sure to check the box that gives the stereo permanent phonebook access if you don't want to be prompted for a sync every day.
If after this you aren't able to stream audio wirelessly, pop back into the Bluetooth menu on your phone, locate your car's ID, and access its options (either by long-pressing the name or tapping the options slider in newer versions of Android). Make sure that both the Media and Phone audio profiles are checked. If you don't see Media audio as an option, chances are that your car stereo doesn't support it. Double-check your car's manual.
Certain Android devices also support a third Bluetooth profile: MAP or Message Access Profile. When a compatible phone is paired with a car that supports this feature, incoming SMS messages can be sent to the vehicle, where they can be read aloud using text-to-speech or viewed via the dashboard interface when parked. MAP is a two-way profile, so the vehicle can also send SMS canned-responses -- such as on my way, running late, or can't talk now -- through your connected phone.
Handset compatibility with Bluetooth MAP has been spotty in the past and at the discretion of the manufacturer, but the profile is built into Android version 4.4 and higher, so we should start to see more consistent adoption soon. Compatibility on the vehicle side, on the other hand, is more limited and slowly growing.
USB is no longer an option (sort of...)
The ability to simply plug your phone into a car stereo via USB is one area where iOS devices still have an advantage over Android (as well as BlackBerry and Windows Phone) devices, even after the great Lightning connector scare of 2012.
Years ago, when I took my first look at methods for connecting an Android phone to a car stereo, USB mass storage connectivity was a shaky alternative method for audio playback of files stored on your phone's microSD card. However, the method was finicky at best, and too many incompatibilities between handsets and stereos forced me to stop recommending that inconsistent hack.
With the jump to version 4.x Ice Cream Sandwich, along with the switch from microSD to internal file storage, Android devices also switched from USB mass storage to the media transfer protocol (MTP). (The change actually happened in Android 3.x Honeycomb, but most users didn't really notice it until thedebuted later in 2011 without a microSD card slot.) The intent was to make Android devices more accessory friendly and to simplify file and storage management when connected to a computer, but the result was that MTP took Android/car USB connectivity from inconsistent to flat out unsupported.
At the time of publication, I can only think of one automaker that supports MTP-enabled Android connectivity: BMW. Even then, it's largely an undocumented feature that only appears on the automaker's most basic "Business Radio" options.
Stock infotainment options
Most people can't run out and buy a new car just because their current set of wheels is incompatible with their smartphone. However, if you are already in the market for a new ride, knowing which automakers and vehicles are available with infotainment systems that are Android-friendly may sway your ultimate choice.
Through a Bluetooth connection to the phone, Ford Sync AppLink-equipped vehicles give drivers control of a wide range of Android apps using little more than the sound of their voice. At time of publication, there are seven apps that AppLink supports: Stitcher, NPR, Slacker, iHeartRadio, and Pandora for audio, and Scout and Sync Destinations for navigation. Simply say, "Sync, NPR News," and you'll be listening to "This American Life" before you know it.
Hop into athese days and you're likely to be greeted by the automaker's new Entune interface (or Enform, if you're in ). This system ties in to an Entune app that is installed on your Android phone, giving touch-screen access to apps such as iHeartRadio and Pandora for audio streaming, MovieTickets.com for browsing for and purchasing movie tickets, OpenTable for making dining reservations, and Bing for online destination search.
Pandora Link is found in both AppLink and Entune/Enform as well as the newest, General Motors' MyLink/IntelliLink, Scion's top-tier receiver, certain systems, and the . Beware: although BMW, Mini, and Mercedes-Benz also offer Pandora integration, their versions are currently only compatible with the iPhone version of the app.
All of these Android and app connectivity systems will make use of Bluetooth, because -- as I mentioned earlier -- that's pretty much the only reliable, bidirectional connection that you can currently make with your Android phone. Even the automakers that I haven't mentioned at this point are going to offer some sort of Bluetooth connectivity for hands-free calling, A2DP, or both as well as an auxiliary input as standard or optional features, so look for these basic connections at the very least.
Some automakers have debuted support for HDMI video, which many Androids can output or use for screen mirroring, but only for rear-seat video. Examples include theand the .
The next big thing: Android Auto
The next generation of Android to car connectivity is just around the corner. Android Auto is a car-specific interface that is "cast" onto the touchscreen that's already on the dashboard of many modern cars.
After connecting a smartphone running Android Lollipop to a compatible vehicle, the phone takes over the dashboard's screen, displaying a simplified version of Google Now with quick shortcuts to Google Maps, commute information, audio sources, hands-free calling and messages, and more. Android Auto places a strong emphasis on voice command and makes use of the host vehicle's steering wheel controls, so you can tap a button and ask for directions to the airport or tap and compose a message saying, "I'm running late."
We've gotten our hands on Android Auto a few times at this point and are very excited about how well integrated it appears to be and the depth of voice command that it brings to the car. A freshly released SDK also allows some of our favorite audio apps (such as Spotify and PocketCasts) to integrate into Android Auto's slick interface.
Perhaps the only constraint to Android Auto at this point is that it only works with phones running the latest Android 5.0 Lollipop and, more restrictively, only when connected to compatible cars. So far, we've only seen Android Auto demonstrated in the 2015 Hyundai Sonata, but the functionality won't be available to consumers until later in 2015. Other automakers, such as Honda, have pledged to have compatibility sometime in 2015, but with such limited support, it may be some time before Android Auto picks up steam.
Yanking out your stock stereo and replacing it with an aftermarket unit may not sound too appealing, but this is often the best way to add smartphone connectivity to an older vehicle while simultaneously boosting audio quality. In addition to your basic Bluetooth and aux-in setups, the aftermarket is often where you'll see emerging technologies appear first.is one of the first to support MHL and HDMI app mirroring to give touch-screen access to the apps running directly on your phone, and you can bet that it won't be the last.
Theand newly announced will also support the MirrorLink standard, which will enable owners of certain Samsung and Sony Xperia handsets to simply plug-and-play for touch-screen mirroring. Alpine and Sony are also among the number of car stereo manufacturers that are supporting the MirrorLink standard.
Check out our roundup of thefor more ideas.
Other things that you'll need
Streaming audio from the Internet, reading your GPS position, and maintaining a Bluetooth connection can be hard on your phone's battery. If you don't want to arrive at your destination with a flat battery at the end of a long trip, then you'll want to invest in a 12-volt USB charger. However, not all chargers are created equal. The standard USB port outputs about 500mAh to 600mAh of current, but many of the large-screened, multicored mega phones that have become the norm will scoff at anything less than 800mAh to 1,000mAh (or 1A). Take a close look at the wall charger that came with your phone for the manufacturer's recommended charging rate and try to match or exceed that number with your car charger. My personal favorite car chargers are the 2-port Anker USB 24W and the quad-port Aukey AIPower 48W chargers.
Beware of 2.1A "iPad" chargers as some of these use Apple-specific variable amperage that renders them incompatible with certain Android phones and tablets. I'm thinking specifically of the older 2012 Google Nexus 7, which is notoriously finicky with chargers. On the other hand, many newer Android devices work just fine with these adapters -- albeit often at a lower-than-advertised charging rate. As is often the case with cars and Androids, your mileage may vary.
You'll also need somewhere to stow your phone while you drive. If you're using a totally hands-free system like a Pandora Link connection, you can simply toss the phone anywhere (a cup holder, the center console storage bin, or your pocket are all good spots).
However, if you're using your phone for navigation and need to be able to use the screen or to interact safely with your phone because you're stuck using an analog audio connection, you might want to invest in a phone cradle of some sort. Many phone manufacturers (such as Samsung or Motorola) will offer specific car cradles for their high-profile phones, but they're usually overpriced and won't be compatible with next year's hot phone, so look for a quality universal cradle that uses a suction cup or adhesive to hold your phone to the car's windshield or dashboard. I like thefor its ability to stick almost any phone anywhere. Your needs may be different, so shop around.
Avoid those "sticky" or "tacky" dashboard pads that simply hold your phone in place flat on the dashboard with little more than friction and gravity. They may be OK for most driving conditions, but you won't want your smartphone becoming an unsecured projectile in the event of a minor accident.
I've already gone over much of what you'll need to know about using an Android tablet in the car as part of the previous "" feature. Nearly every tip in that article can be applied to any Android tablet on the market.
Possibly the best place for any tablet in the car is in the back seat, and you'll need either a DIY or universal mount, if you plan on hanging an Android tablet from the headrests as you would with a traditional rear-seat entertainment system. I'm of the opinion that, with the exception of very young children, most users would probably be better served simply holding the tablet in their hands, so you probably shouldn't even bother with the mounting unless you're trying to be fancy.