Limitations with radio frequency identification technology have delayed a nationwide rollout at UK-based supermarket giant Tesco by several years. Tesco had planned to install RFID tags and readers in 1,400 shops and 30 distribution centers by the middle of this year, but has so far completed just 40 stores and one depot. Instead of tagging individual products, it will now permanently tag transport items such as cages and trolleys and install the technology over several years.