[card_zero]

Hmm. If the diameter of the circle that the car drives in is 14 meters, that works out as ... 54657 mph. I cannot endorse this from a safety standpoint.

Wait, no, I was working in km instead of m, it's only 54 mph. Should be fine.

[dmurray]

It's one revolution every 1.8 seconds. That seems too fast for most roundabouts, but maybe not uncontrollably so.

78 rpm is Formula One territory.