The Brief A new Phoenix ordinance that went into effect on Jan. 15 requires retailers to keep shopping carts on-site using GPS trackers, locking wheels, or professional retrieval teams. Go to any big city, and you’re likely to spot shopping carts far away from the stores they come from. Local perspective:"For many years, the city of Phoenix has had challenges with abandoned shopping carts," said Lucas Mariacher of the City of Phoenix Services Department. "Each shopping cart is outfitted with a caster — when it reaches the boundary, the cart locks, preventing it from leaving the property," Cooper said. What you can do:To report abandoned shopping carts, call 602-534-4444 or report it online here.