is it legal to carry 4 passengers in rear seat of a sedan?

Sheesh. What jurisdiction?

in Kansas,
thanks

Kansas is kinda like the Wild West as far as rules.

No ticketing of rear seat passengers for no safety belts.
3 in the front is a law, but to my knowledge, the back seat is for whatever you want, as long as everyone is inside the vehicle.

Even if it is on the books, it is doubtful to be enforced. I have been involved in situations where a stop was made, with more than 3 in the back(in Kansas), and it was never mentioned.

Thanks buddy, I am planning a shopping trip, and a lot of my friends want to go with me/