Now you don't.
I drove my invisible car to work and back home again today and have most of the week. Like the Emperor's New Clothes to the Emperor, it's not invisible to me - I can see it, touch it, hear it, wonder if it's ever going to rain enough to wash the dust off it. But ...
And it's a big but (Hey, I just got that!)
To other drivers, my car must be invisible and when I'm riding it, I myself can not be seen. Why else would people make right turns at stop lights in front of my moving car? Every day? Several times a day?
Sometimes I'm tempted to speed down the highway in my invisible car. If I could only see the faces of the state troopers who clocked an invisible vehicle going 90 miles an hour.