The definition of NOx in MOVES (NO + NO2 + HONO) is different than the standard NOx definition of NOx (NO + NO2). This change has been made to correct the exhaust NOx emission in MOVES for potential interference with HONO measurements. MOVES users should consider which measure they would like to use depending on their use-case. For example, for comparing NOx results with a vehicle emission test program, MOVES users may want to simply use NOx, whereas MOVES users developing air quality inputs of NO, NO2, and HONO, should estimate NOx as the sum of NO and NO2, rather than using the direct NOx output in MOVES.