A driverless shuttle bus hit an aircraft tow tractor inside a restricted zone at Hong Kong airport on Tuesday, marking the second collision involving the unmanned vehicles in two months. The accident, which did not result in any injuries, occurred around 3pm when the bus, which was not carrying any passengers, detected an obstruction and came to a stop. According to the Airport Authority, a duty officer mistakenly instructed the bus to resume its movements, resulting in a minor collision with...