ModNation Racers: Road Trip does not offer head-to-head online multiplayer, developer SCE San Diego has confirmed.
Speaking in a live chat session hosted on the US PlayStation site yesterday (thanks VG247), producer Vernon Mollette explained that online play is restricted to track sharing, leaderboards and swapping ghost data with friends.
If you want to race your friends in real time, you'll need to be in the same room and all own a copy of the game.
This is at odds with the 2010 PSP version, which supported six player online head-to-head races.
ModNation Racers: Road Trip is expected to be available from the Vita's 22nd February launch.