The in-game Tobin scan registers them as Class IV Full Roaming Specters.
They can rocket towards you causing a lot of harm, so be careful not to stand in their way when they rev their engines.
Found only in Multiplayer Mode, these ghosts were once a fraternity of like-minded club members, fond of wheeling around on little scooters. They now haunt the streets of Times Square as well as the "Rooftops."
They are characterized by rotund bodies driving around in a mini go-cart. Various ghosts have different numbers of American flags hanging from their cart. Most of them wear fez hats.