Walmart is building four of what it calls next generation fulfillment centers over the next three years, the first opening this summer in Joliet, Ill.

“These FCs will be the first of their kind for Walmart, using the powerful combination of people, robotics, and machine learning to set an entirely new precedent for us on the speed of fulfillment while continuing to create a positive work environment for our associates,” the company explained.

It partnered with Knapp, a provider of intelligent fulfillment solutions, to develop an automated, high-density storage system that streamlines a manual 12-step process into five steps.

Following a pilot study conducted at one of its centers, David Guggina, senior vice president of innovation and automation, said “We have seen how the benefits of this technology are wide-ranging and include: more comfort for associates, double the storage capacity and double the number of customer orders we’re able to fulfill in a day.”

The four new FCs are expected to provide 75% of the U.S. population with next- or two-day shipping on millions of items, including Marketplace items shipped by Walmart Fulfillment Services.

“Combined with our traditional FCs, we can reach 95% of the U.S. population with next- or two-day shipping, and by making use of the expansive reach of our stores, we can offer same-day delivery to 80% of the U.S. population,” Guggina noted.

The facilities will employ over 4,000 associates, including tech-focused jobs like control technicians, quality audit analysts and flow managers.

“Our priority is to strategically locate our FCs to pair most effectively with our 4,700 stores and 210 distribution centers,” Guggina said. “Together, this system of fulfillment assets is optimized to get orders to customers fast and efficiently.”