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, auto makers 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.
A matter of timing
Alison Conway, associate professor at Grove School of Engineering at City College of New York, said growing demand for short delivery times has increased the number of neighborhood fulfillment centers, also known as microwarehouses, springing up, and that means more trucks rolling into cities.
Then there's the fact that traditional parcel and e-commerce deliveries happen at different times of day. The streets in many urban areas have signs that allow for deliveries until midmorning. The streets then switch to metered parking. But e-commerce deliveries can happen on a different schedule, so there may be nowhere for delivery vehicles to park.
"E-commerce has changed the spatial distribution of where (traditional parcel) vehicles need to park, and we are just starting to figure out what changes need to be made to the network," Conway said.
Consider groceries. In New York, Trader Joe's, FreshDirect, Amazon and Blue Apron are just a few delivery options.
"Trying to piece all of those out and get a handle on the impact that it's having on traffic is something that I think we're only at the early stages of figuring out," she said.
Allan Rutter agrees. He is the division head of the Freight and Investment Analysis Interdisciplinary Research Group at Texas A&M Transportation Institute. Rutter said it's far too early to know how the tremendous growth of e-commerce will affect urban traffic because some trends are still developing. The number of new customers signing up for grocery deliveries will be a big factor, he said, as will the expansion of e-commerce to people previously unable to participate.
At the same time, the e-commerce trend also is sparking a search for better ways to use technology to get products to customers' doorsteps.
One scenario is to use a combination of driverless vehicles and delivery robots.
This year, supplier Continental demonstrated a package delivery system that employs a robotaxi called CUbE, short for Continental Urban Mobility Experience, and a miniature delivery robot.
"Both are electrified, both are autonomous and, in principle, both can be based on the same scalable technology portfolio," Ralph Lauxmann, head of systems and technology in Continental's Chassis & Safety Division, said in a statement.
Driverless vehicles such as CUbE could act as a kind of mother ship, carrying one or multiple delivery robots and deploying them to handle the last yards of the delivery logistics chain, according to Continental. The goal is to reduce idle times spent in traffic and boost transport capacity.
Amazon has been testing a similar last-mile delivery system called Scout. The devices use camera and sensor data for autonomous route planning and navigation to transport parcels from urban distribution points to customers, according to the company. So far, the robot has been tested in Washington and California.
In Memphis, FedEx has tested a short-range robot, Roxo, that can travel on sidewalks, along roadsides, on unpaved surfaces and up and down steps.
Ford Motor Co. announced the initial testing of its package-carrying, two-legged headless android concept named Digit in May. Unlike some wheeled delivery robots, Digit could use its arms and legs to ensure safe delivery of packages.
And Nuro, a self-driving delivery company, has tried grocery and pizza delivery programs through partnerships with companies such as Kroger and Domino's.
What happens when all these robots hit the pavement is an open question.
Rutter points to the user confusion and sidewalk congestion caused by electric scooters and rental bikes as a preview of the problems with autonomous robots.
"Fixing the first and last mile is a challenge for a whole bunch of operations," he said. "If you have little coolers on wheels and those are on sidewalks, how do those fit in areas that don't have as big a sidewalk as other places do? So many of these operations are being driven by technology firms, which are much more of the ask-forgiveness-later mentality. I think it's going to be a challenge for a lot of city planners and city governments."