The final major task for Mbsetup is to create the speed summary SMOKE intermediate file (SPDSUM), which is needed by both Premobl and Emisfac. The file lists all the sources in the inventory that need speeds, and the speed value to use for the source or the speed profile code for that source; the source’s MOBILE6 facility type (freeway, arterial, local, or ramp); and the reference county to be used for that source. This file is created in such a way that sources in the same reference county that share the same speeds will be grouped together, so that the MOBILE6 calculation of their emission factors will need to be done only once in the Emisfac step.