Triple population of the little town where I grew up.

Sad day.

I'm driving down the road today...

...and I see a Prius. Then another Prius. Then I begin to wonder - what's the plural of Prius? If the plural of "cactus" is "cacti", and the plural of "octopus" is "octopi", then is the plural of "Prius" "Prii"?

Then I had to stop thinking about it and go back to hollering at the people that don't know how to drive.