The present invention is an improved cart coupler assembly for use on a shopping cart retriever vehicle. The cart coupler assembly provides a means for connecting shopping carts to the cart retriever vehicle. The cart coupler assembly may employ an actuator to move yokes into position to enable the yokes to engage shopping cart members. The cart coupler assembly may employ the upwardly facing concave surfaces of U-shaped yokes to engage the rear wheels of a shopping cart. In the place of yokes, the cart coupler assembly may utilize a shopping cart emulator that emulates one or more portions or features of a shopping cart in order to facilitate the engagement of the coupler assembly to a shopping cart.