How are SmartWay trailer aerodynamic kits and low-rolling resistance tires quantified for SIPs and transportation conformity determinations?
For states other than California, EPA recommends the use of the National Mobile Inventory Model to estimate emission reductions from SmartWay aerodynamic kits and low-rolling resistance tires for SIPs and for transportation conformity analyses. The model estimates the impact of these technologies for the particular years to which they apply under local conditions. Due to the nature of the aerodynamic kits and low-rolling resistance tires, emission reductions from them will vary based on the average speed of the vehicles. See Chapter 2 of the guidance for more information. State and local agencies developing SIPs and conformity analyses for California should consult with EPA Region 9 for information on the current version of the emissions factor model approved for use in California and for information on how to apply Chapter 2 of this guidance with California’s model.
