OAKLAND, N.J. -- A ShopRite supermarket here is testing on-cart video technology that displays ads from product vendors and information about store specials, according to Media Cart, the technology provider. The test, which includes 210 shopping carts, has been in place for about three weeks and has received “very positive” feedback from customers, according to Jon Kramer, chief marketing officer, Media Cart Holdings, Plano, Texas. A spokeswoman for Wakefern, the Elizabeth, N.J.-based cooperative that supplies ShopRite stores and is responsible for ShopRite media relations, could not be reached for comment. In coming weeks, the Media Cart test is slated to expand to include additional functionality, including price checking and item location. The technology can also be used to display recipe and nutritional information and to total the contents of baskets prior to checkout.