Japanese machinery makers are developing more unmanned construction equipment to help builders cope with labor shortages.
For example, Hitachi Construction Machinery is developing hydraulic excavators that can dig a construction site without a human operator for each device.
The autonomous machine uses sensors at the worksite to detect soil conditions and to position itself.
The company is aiming to put the diggers into practical use within a few years.
Imura Shinya of Hitachi Construction Machinery said, "The system allows one person to operate multiple machines. That will help reduce the number of workers needed at construction sites."
Hitachi Construction Machinery rival Komatsu has developed a system for remote-control of heavy machinery.
Komatsu's testing apparatus shows an operator sitting in what looks like an aircraft cockpit. Seven monitor screens show a worksite from various angles, allowing the equipment to be run remotely.
Labor shortages have been affecting Japanese industries, including builders, as the population shrinks and ages. Government figures show more than a third of construction workers are at least 55 years old.