A drone recently launched from the top of a UPS package car, autonomously delivered a package to a home and then returned to the car—all while the driver continued along the route to make a separate delivery.

The test was conducted earlier this week in Lithia, Fla., according to a news release. UPS worked with battery-electric truck and drone developer Workhorse Group, who built the unmanned aircraft system (UAS) and the electric UPS package car used in the test. The drone, known as the Workhorse HorseFly UAV Delivery system, is an octocopter that’s integrated with Workhorse’s line of electric/hybrid delivery trucks.

During the test, the battery-powered drone, which has a 30-minute flight time and can carry a package that weighs up to 10 pounds, docked on the roof of the delivery truck. The UPS driver loaded the package into a cage, which was suspended beneath the drone and extended through a hatch into the truck. The driver then pressed a button on a touchscreen to send the drone on a preset autonomous route to deliver the package.

“This test is different than anything we’ve done with drones so far. It has implications for future deliveries, especially in rural locations where our package cars often have to travel miles to make a single delivery,” said Mark Wallace, UPS senior vice president of global engineering and sustainability, according to the release. “Imagine a triangular delivery route where the stops are miles apart by road. Sending a drone from a package car to make just one of those deliveries can reduce costly miles driven. This is a big step toward bolstering efficiency in our network and reducing our emissions at the same time.”

Rural deliveries are the most expensive, according to the release, but with UPS’s On-Road Integrated Optimization Navigation routing software (ORION), reducing one mile per driver per day for a year could save up to $50 million.

For the test, Workhorse preset the drone’s route, but in the future routes could be determined by ORION, according to the release.

This isn’t the first time UPS has tested drone technology. Last year, UPS staged a mock delivery of medicine from Beverly, Mass. to an island three miles off the Atlantic coast. UPS deploys drones for humanitarian relief and is working with third-party organizations to deliver blood and vaccines in Rwanda. UPS also uses drones to check inventory in its warehouses.

This most recent test represents the first time UPS has shown how UAS might be used to help in daily residential deliveries, according to the release.

“It’s wonderful to see this technology applied in such a practical way,” said Stephen Burns, Workhorse founder and CEO, according to the release. “The drone is fully autonomous. It doesn’t require a pilot. So the delivery driver is free to make other deliveries while the drone is away.”