Abstract: Robotic, autonomous mowers are programmed and configured to avoid collisions with each other. Each mower may include a transceiver allowing direct machine-to-machine digital communication with other mowers over a wireless data channel. Each mower may periodically transmit a digital data packet that may include navigational information and/or a priority code such as a machine serial number. Detection of such a data packet may be used to alert a mower to the presence of another mower nearby. The navigational information may include a stored mow path map or mow path timetable showing the mower's current location and the path the mower is programmed to follow in the coming seconds or minutes. Comparison of a mower's own mow path map with that received from the other mower may be used to declare a hazard condition. Comparison of the priority codes may be used to determine which mower is to take evasive action.