It happened just before midnight Monday on westbound I-540 near Leesville Road.
The NC Highway Patrol said 39-year-old Bently Cornell Foreman was driving the moped on I-540 when he was hit from behind by a car and thrown off the moped.
The driver of the car said he didn't see the moped.
Slow moving vehicles like mopeds are illegal on interstates.
No charges have been filed.