Click by click, it's growing.
According to the U.S. Census Bureau, e-commerce, as a percentage of all U.S. retail sales, has been climbing for the last decade, from about 4 percent in 2010 to almost 11 percent in the first quarter of 2019.
As consumers buy more goods online, the search is on for ways to improve package delivery timeliness and efficiency. For some delivery companies, automakers and suppliers, the answers may lie in autonomous technology.
Meanwhile, officials are sorting out a more immediate issue: what long-term effects the e-commerce boom is having on America's cities, in particular on traffic.