Glendale, a suburb of Phoenix, had approved the zoning for the store more than a year ago. In July, Wal-Mart signed a lease for the parcel at the corner of 51st and Olive Avenues. But now the city has hired a local land-use attorney to conduct studies on traffic, street intersections and entrances.

The move caught Wal-Mart off guard. The company thought plans were progressing and had no idea that the city had hired an attorney to review the plans, says Amy Hill, a spokeswoman for the retail giant.

Glendale is one of four Valley cities, along with Tucson, that either have controls or are considering creating controls over supersize stores by setting limits on their size and where they can be built.