At your door in minutes, delivered by robot

But given the explosive growth of e-commerce, some experts say the shipping business is in for big changes. United Parcel Service, which traces its history to 1907, delivers more than 4 billion packages and documents a year. It operates a fleet of more than 95,000 vehicles and 500 aircraft. The ubiquitous Brown is a $55 billion-plus-a-year business. And, like Amazon, UPS is reportedly looking into drones. So is Google. More and more e-commerce companies are making a point of delivering things quickly the old-fashioned way -Making Robots More Like Us with humans.Some of the dreamers in the technology industry are dreaming even bigger. It won't be just drones, they insist. Robots and autonomous vehicles - think Google's driverless car - could also disrupt the delivery business.

"As cities become more automated, you're going to start to see on-demand delivery systems that look like small delivery vehicles and can bring you whatever you want to wherever you are," said Bryant Walker Smith, a fellow at the Center for Internet and Society at Stanford Law School and a member of the Center for Automotive Research at Stanford. "Rather than go to the store to buy some milk, a robot or drone will go to a warehouse and get it for you, then deliver it."Smith said these delivery vehicles would come in all shapes and sizes. Some might be able to scurry down alleyways and avoid traffic. Others could be refrigerated to store food.

Brad Templeton, a futurist and a member of the board of the Electronic Frontier Foundation, said the current systems for delivery - "with the exception of pizza" - were too cumbersome and expensive for today's online shoppers. Autonomous vehicles, including drones, promise a faster, cheaper option."The cost of use will be pennies on the dollar compared to today's delivery systems," Templeton said. This, he added, could very quickly eat into the business of many delivery companies."None of the horse and carriage companies of the past ended up becoming automobile companies today," said Templeton, who is also a consultant on the Google team designing a driverless car.The roadblocks, real and potential, are significant. Safety is one worry. Another is current technology. Drones like the ones showcased by Amazon are electric and are estimated to be able to carry only small packages weighing less than 5 pounds. That means they would not work for most online purchases.