You pay two separate fees.
1 pass for each car. And they are window stickers with RF tech that don't remove without damaging the RF...in other words, no cheating
It would be one sticker for each car.
What if you have six cars? Buy a pass for each one. They will never sell a tranferable pass as you could give washes for your friends and neighbors too (or maybe that is what you want to do.)
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