Is robotic mail delivery far off?

Most of us may now be familiar with the Google driver-less cars that have been roaming Southern California for the last several years. Google says that these cars have now clocked more than 300,000 miles on all kinds of roads. According to the New York Times, most major automobile manufacturers are also working on self driving systems in one form or another.  Japanese truck maker Komatsu has now sold 150 driver-less trucks to be operated in the Rio Tinto Pilbara iron ore mines in Western Australia. These trucks will be controlled from an operations center in Perth, more than 1000 miles away.

On the other hand, industrial robotics have now been in use in the manufacturing for at least two decades. According to the Robotic Industries Association (R I A), 225,000 industrial robots are currently in use in the United States.  A great deal of advances in robotic arms have resulted from the development of increasingly sophisticated mechanical hands. Robotic limb technology is advancing in leaps and strides, but it is mechanical hands that have seen the greatest recent improvements.

Vision, automobile control, robotics, all the technological elements are almost there to create a vehicle capable of delivering mail.  This will likely apply first to a small portion of addresses in the United States, curb mailboxes easily accessible from the street.  Delivery labor costs amount to 80% of USPS costs today.  Would it not make sense for the U.S. Postal Service to investigate robotic mail delivery?