Occasionally I shop at the Publix Supermarket just around the corner. During my last trip I noticed a sign on the front of my shopping cart:

“This shopping cart will automatically stop if taken beyond the yellow line at the end of the parking lot”

I thought it was a joke – or at the very least, an idle threat designed to make people think twice about taking carts out of the lot. Now I find out this a new technology that actually works. It is estimated that up to $800 million worth of shopping carts go missing each year in the U.S. alone. Often, they are used by homeless people to carry their belongings, and the carts are eventually abandoned alongside roadways, in alleys, culverts, and streams. Since Sarasota has a sizable homeless population, it is not uncommon to see these abandoned carts on my daily walk to downtown. Just today, I spotted a Whole Foods cart in an unused parking lot two blocks from my apartment. But to the best of my recollection, I have never seen a Publix cart outside of their lot.

When this Publix was built last year, a yellow line was painted around the perimeter of the parking lot. Buried beneath the yellow line is a thin wire that receives a low power FM frequency from a nearby transmitter. Each shopping cart is fitted with an electronic locking wheel, or ‘boot,’ which locks when it receives the electronic signal from the wire. The cart will not roll until the transmitter broadcasts the unlock frequency. Since minor injuries have occurred to people’s wrists and arms when the cart abruptly stops, I suspect it is only a matter of time before someone sues Publix for damages when they are injured by this technology, despite the fact that their injuries were received as a result of their attempted theft of the cart. Won’t that be a kick in the pants!