The radical car and the kanji car are exactly the same.
When we need to remember the reading しゃ, we use "shaman".
There's a car. It's the nicest car you've ever seen. Exquisite, beautiful. Wouldn't you be surprised to learn it belongs to a shaman (しゃ)? Well it does. This shaman charges a premium for his shaman services so he can afford fancy cars like this.