Once one or two people get on the cart, the rezzer place a new one. In turn, when your customers getting off the cart, it disappears. There is no question of exhausting your prims with carts lying around.
Tap the handle to drive the cart, or touch the body of the cart to sit and relax,You can choose three different animations.
The driver has a full menu to position its avatar and choose diferent handle heights.
Have a look in Ñam Store