Cyclocross is not a road bike, it's a cyclocross bike!
It's a bit different...
Cyclocross bike are used in race with also paved road, but above all path with mud and/or grass. Sometimes riders must walk with their bike on the shoulders upstairs (some steps in the path...).
Mainly difference in the bike:
-smaller chainrings (e.g.: 46-36, 48-36... Someone use a single 42t chainring)
-cantilver brakes (not common road brakes)
-up-pull front derailleur (I don't know if it's the righe name... Anyway, front derailleur wire comes from up, not from down as in common bike)
-a bite different frame as regard geometry (e.g.: cyclocross frames allow wider tires)
-someone uses a second couple of brake levers
-32-40mm tires for riding on the grass and on mud