One embodiment is a method including a unique soot loading metric. The method includes treating exhaust with a soot filter, sensing information including a pressure differential of the soot filter, a temperature of the soot filter, an ambient pressure, an air flow, and a fuel flow, evaluating the information to determine a value, and commanding a regeneration of the soot filter based upon the evaluating. The evaluating the information to determine the value accounts for a first contribution to the pressure differential attributable to laminar flow wall friction and a second contribution to the pressure differential attributable to turbulent flow. Another embodiment is a system including a unique soot loading metric. The system includes an exhaust aftertreatment subsystem including a soot filter, a controller operable to receive information of a pressure differential of the soot filter, a temperature of the soot filter, an ambient pressure, an air flow, and a fuel flow, to evaluate the information to produce a value, the value accounting for a laminar flow contribution to the pressure differential and a turbulent flow contribution to the pressure differential, and to command regeneration of the soot filter based upon the value.