When was the last time you spent a whole week only listening to the radio in the car—no phone calls, no mp3 player—just the radio. For a growing number of Americans, radio is just one of many media options behind the wheel—a reality that radio must address to remain competitive.

Depending on the format, some stations earn over 60% of their AQH (average quarter hour) audience share from in-car listening. In fact, you’d be hard pressed NOT to find a market in the USA with at least one station that has lost time spent listening with audience at-work and at-home, but has largely survived on in-car listening.

Some food for thought this week:

1. How much do you depend on in-car listening at your station?

2. What percentage of your AQH share comes from listeners who turn on the station in the car?

3. When was the last time you took a realistic look at how your audience consumes your station in the car?

New competition with the AM/FM car radio is showing up every day.

Case in point, Ford is targeting Generation Y—the 57 million people born between 1981 and 1995—with a product you’ve probably heard about called Ford Sync. Ford and Microsoft developed the in-car communications and entertainment system collaboratively. Since 2008, it has been a factory-installed feature in most Ford, Lincoln, and Mercury vehicles in North America.

Sync uses Bluetooth and USB to connect with portable media devices like the iPod and Zune.

Sync is under continual development by Microsoft and Ford as new mobile devices enter the market. In the last year, they have added traffic alerts (unfortunately, usually more accurate than radio traffic reports), turn-by-turn directions, weather, sports, news, and 411 business search. They have even added Vehicle Health Reports, where users can access free reports based on preferences set online.

RIM’s BlackBerry’s and smartphones using Android software all have free applications that play music streams. Moreover, the audience can customize most of the music channels and stream them right to their phone.

Another alternative to broadcast radio, Pandora Internet-Radio, reports that they doubled their listeners when their iPhone app became available—making it possible for people to listen to Pandora on car radios.

Car stereo manufacturers, Pioneer and Alpine, have even recently released receivers with customized PANDORA LINKS.

The best news is that smart radio operators can participate in the mobile trend by getting into mobile apps, streaming, and carefully thinking through the usage and delivery of their “drive time” products.

According to the 2010 Arbitron/Edison Media Infinite Dial Research, mobile phones and AM/FM Radio are two of the three most ubiquitous media devices in the USA.

How can you take advantage of this trend at your station?

More about that question coming up in next week’s Radio 3D.