On XXX, I parked my 2016 Ford F-150 in a Kroger parking lot, in [XXX] around 5 pm. I placed the transmission selector in PARK, exited the vehicle, and went inside the store. The vehicle was unattended. When I came back outside, I discovered that the truck had rolled from where I had parked it, traveled across the parking lot, and struck another vehicle. A police report was filed regarding the incident. I believe there may have been a failure of the vehicle's parking mechanism, transmission, shift linkage, transmission range sensing system, or another component responsible for preventing the vehicle from moving while in PARK. The current answer is UNKNOWN. The incident created a serious safety risk because the unattended vehicle was able to roll freely through a public parking lot where pedestrians and other vehicles were present. Fortunately, to my knowledge, no one was injured, but the vehicle did strike another vehicle and caused property damage. At this time, the problem has not been reproduced or confirmed by a Ford dealer or independent repair facility. The vehicle has not yet been inspected by Ford to determine the cause of the rollaway. Police responded to/documented the incident and a police report was completed. I did not observe any warning lamps or warning messages indicating that the vehicle was not properly in PARK before exiting the vehicle. I had no indication that the vehicle would move after I exited it. I am reporting this incident because the vehicle