Earlier this week, we reported that a strong majority of radio’s top execs are, as a group, optimistic about traditional radio’s future. But that doesn’t mean they’re oblivious to the challenges facing radio, especially, the biggest one…

In our survey of radio general managers, group execs and owners, the challenge from new technology looms large, as you would expect.  When we asked them to volunteer the “single biggest threat” to traditional radio, more than one in five named the internet, smartphones and digital media in general, including in-car internet access.

Keep in mind that these were responses volunteered by radio execs — top-of-mind, unaided.  When we delve deeper, in-car internet looms much larger…

We asked them to rate seven traditional radio competitors as a “big threat,” a “small threat,” or “no threat.”  And we found that, by a wide margin, they think  in-car internet is the threat to traditional radio:

% naming “a big threat”
Internet Access in Cars     41%
Pandora     18%
Sirius/XM Satellite Radio     13%
iPods/mp3 Players     13%
Podcasts       8%
iHeartRadio       7%
YouTube       6%

Perhaps just as “impressive,” another 42% consider in-car internet as a small threat to traditional radio. So, altogether, 83% consider it a threat. That exact percentage holds even for execs who say they’re “optimistic” about radio’s future (though fewer of them — still 32% though — consider it a big threat).

What this all means is: Even if you’re optimistic about radio’s future, you know it’s facing a tough battle.  And that battle will be on wheels.