The stores in the US mostly have metal "Cart Corrals" where you return the cart. They send out someone to collect them every now and again. This keeps the carts away from the cars, so you don't get dents. But of course, there's always a few lazy people who just leave them all over the place, or (my favorite) launch them towards the corral and turn their back and walk away as the cart careens off-course.

Aldi's system certainly encourages "correct" behavior, but I'd rather not have to take the cart all the way back to get my coin. Especially in a parking lot the size of the typical Costco or Walmart. I'd just hand the cart over to the next arriving customer so I can leave quicker.

As I commented below, there's nothing preventing having both systems. Most European supermarkets have the "cart corrals" with built in coin chains.

You can als just abandon your cart. Someone else will be happy to earn a Euro returning the cart.

Yup. Aldi is the only place in the USA I've seen this. Everywhere else people can and do leave carts all over the parking lot even though there are return sections in the middle of the lot. Many just leave right in their parking space because they are too lazy to walk 20 feet to the nearest collection bin.

Yep. There are stalls for cart return around the parking lot. There's a fair amount of theft. Derelict shopping carts floating around are one of the most reliable markers of a sketchy neighborhood.

In Chicago, some places have a little square outside the main entrance with posts too narrow to fit a shopping cart through, or an "invisible fence" system that locks up the wheels if the carts are brought past a certain line. In that case you have to bring your car around to the loading area and the cart always stays inside the perimeter.

In the US, only Aldi and some urban based supermarkets where homeless people and drunks will run off with the carts use them.

More often these days, they just put an electronic wheel lock on the front wheel to disable the cart when it leaves the lot.

In the UK, it's not the case. Most have carts that have no such feature, though a good proportion do. From my own anecdotal experience living in less desirable areas, the use of the coin system tends to be in areas that would be more likely to have carts taken/stolen.

I think most places used to have the coin system, but it's often been replaced with a wheel lock. There's a wire loop at the perimeter of the car park, which clamps a brake on the rear wheels if the trolley is passed over the loop.

The two systems clearly solve different problems. The coin system is to encourage people to put the cart back in place; the wheel lock to prevent people stealing a cart. A euro fir a cart is not a bad price, if you need one to take with you.

At a branch of downmarket discount retailers B&M recently, I asked the cashier if I could make some change for a trolley. He handed me a sardine-can key and asked if I knew how to use it.

That jimmying the coin operated locking mechanism with part of a tin of fish is considered semi-common knowledge leads me to suspect Britain's trolly theft problem is endemic!

I've also bought a tin of sardines. Just in case.

In our area we have wheel and coin locks. Wheel locks only work in retail parks though as there are too many possible exits in other locations.

In the majority of US supermarkets, there are receptacles in the parking lot for carts. You just find the nearest one and push it in there and leave it after loading your car. It saves a trip back to the store. Later, a store employee will push a line of 20+ carts back all together to the store.

We have this in most supermarkets in Europe, but the receptacles have the chain and key for retrieving your coin. Employees typically carry a fake coin on a keyring for bringing the lines back to the shop.

(Supermarkets also sell branded versions of the fake coins for customers too accustomed to arriving with no spare change for a trolley)