It's certainly the word for the straight bit in a race track.
The more I thitnk about it, the more I think we say "that straight straetch." I'm trying to think of when I'd use it.
You know where Miller Road has that straightaway, past the golfcourse? That's where I got my speeding ticket.
But I think I'd proababy be more likely to say "that straight stretch past the golf course on Miller Road."