A method for autonomous navigation of an autonomous vehicle includes: estimating a stopping duration, for the autonomous vehicle to reach a full stop, based on a current speed of the autonomous vehicle; calculating a critical time from the current time by the stopping duration; detecting an object in a scan image, of a field proximal the autonomous vehicle, captured by a sensor on the autonomous vehicle at the current time; based on the scan image, deriving a current location and motion of the object; calculating a future state boundary that represents a ground area accessible to the object up to the critical time based on the current location and motion of the object and a set of predefined motion limit assumptions for generic objects proximal public roads; and electing a navigational action to avoid entry into the future state boundary prior to the critical time.