Been clueless for years. Driving me insane.

I've had a song stuck in my head since I was young and I've never been able to work out the name, and I was wondering if you lovely people could help in any way at all!

All I reeeeeally know about it is that it was on the radio in the UK pretty prominently around 2004/2006. I only vaguely remember the rhythm and tune of the chorus, not the lyrics. It could've been

"I'm on the altern highway, on the altern hiiigh, ten thousand years, since I said goodbyyyye" (my gut feeling)

But parts of that could easily have been swapped for "one turn highway", "five thousand years", "gimme one good reason" etc.

I'm sorry for being so vague, I've been searching for the song for literally years now but since I only remember that one section google etc haven't been much help

I also remember hearing it in a movie aimed at young teens, but all I remember from the movie is that there was some generic kids on a journey with a weighty black man who was one of Hollywood's typical "whacky fun guys". It was a comedy.

Again, I'm really sorry for being so vague. I feel like I'm being "that guy" for asking such a silky question but it's really driving me insane, I want to hear the song again!

In summary:
2006, UK Radio (probably Kerrang), sounded like "I'm on the altern highway, I'm on the altern high, ten thousand years, since I said goodbye", pop style for the time (I guess Coldplay's kinda style), and I'm sorry

I should probably add:
Man singing, gentle voice, song didn't require him to utilise much of his vocal range, had drums and I think electroacoustic guitar

What's an "altern" highway? I was thinking it was something like "110 (one ten)/Alton/Dalton highway". Since you aren't sure about the lyrics, it might be easier to identify the movie. Was it something R-rated like Road Trip or more PG-13 like the National Lampoon Vacation movies? Do you know more details about it?

The movie, "Are We There Yet?" starring Ice Cube fits your description. It was released in 2005. The following link shows the songs from the soundtrack.

http://www.imdb.com/title/tt0368578/soundtrack

I was thinking Johnson Family Vacation

Are the lyrics possibly "I'm on an all time high"?

That doesn't help much, but...