Aldi in Ireland (and I'm assuming the rest of Europe too) has a new system in place. If sensors above the checkouts detect the lines are too long an automated voice will announce "Checkout 2 will open soon, please start unloading your goods on to the belt". 30 seconds later another announcement will say "Operator to checkout 2 please" so the operator arrives to a checkout with a fully loaded belt.
And the reverse happens as well, when the line reduces another announcement will state that the checkout is closing and customers should not approach that checkout.
I'm always amazed at the little things Aldi does to make their process even more efficient.
I've seen these at Lidl in Germany, too. It's really great; when a new checkout opens, I see the green light coming up and can immediately take first place in that queue.
One trick that I find helpful: When in the queue, leave some space to the person before you, to make the queue appear longer and thus incentivize the cashier to open the next checkout.
And the reverse happens as well, when the line reduces another announcement will state that the checkout is closing and customers should not approach that checkout.
I'm always amazed at the little things Aldi does to make their process even more efficient.