They’re called “empty miles” and they help add millions of tons of emissions to trucking’s emissions footprint. Convoy—a winner of Fast Company’s 2020 World Changing Ideas Awards—has an app to help truckers always make sure they have something to haul. Shipping products—produce, electronics, anything else you buy that wasn’t made locally—across the U.S. has a massive carbon footprint. But those emissions don’t just come from the sheer distance of trucking boxes from, say, the Port of Los Angeles to Chicago or Memphis. Another part of the challenge comes from how the trucking industry operates: It’s not uncommon to make a delivery and then turn around and drive back hundreds or thousands of miles with an empty truck if a driver can’t easily find another delivery to make on the return trip.