Ghost 2000...
OK! Simpler than I thought... you just had the car parked at the beginning of the exposure, then started moving while the shutter was opened. You did a circle, then drove down the street. I get it now. 
I was overanalyzing.

I was overanalyzing.
you could get a similar effect with a long shutter open and a sync for the flash to fire right before the shutter closes.. This will 'freeze' the action at the time the flash fires. Conversely a sync when the shutter opens will 'freeze' or better expose the image seen when the flash first fires!



