An interferometric micro electro-mechanical switching device includes an interferometer. In one embodiment, a method comprises erasing a predetermined percent of rows in a memory block, analyzing a number of erase pulses used to erase the predetermined percent and calculating an acceptable number of additional erase pulses which could be applied to the memory block to erase the remaining rows. The light assembly becomes lighted when a reverse gear is entered. Rate of change of flow resistance through the aftertreatment element over time is correlated with at least a model of particulate matter accumulation within the aftertreatment element and a model of regeneration frequency of the aftertreatment element, based on predetermined values for particulate matter accumulation and regeneration frequency.