SHIFT Calculator - Methodology

The SHIFT Calculator estimates induced travel—the increase in vehicle miles traveled (VMT) following road capacity expansions—using empirical elasticities. It applies a 1.0 ratio for interstate highways and 0.75 for other freeways and arterials, predicting that a 1% increase in lane mileage leads to a corresponding increase in VMT over 5 to 10 years. The tool also calculates cumulative greenhouse gas emissions through 2050 based on two scenarios: a business-as-usual case and one aligned with the US Nationally Determined Commitment (NDC), which assumes 100% electrification of new passenger vehicles by 2035.

• The SHIFT Calculator estimates long-run induced VMT (steady state in 5 to 10 years) by applying specific elasticity ratios based on road type: a 1.0 ratio for interstate highways (Class 1) and a 0.75 ratio for other freeways, expressways, and principal arterial roads (Class 2 or 3).
• Induced travel is driven by economic principles of supply and demand, where increasing roadway capacity reduces travel time and the 'price' of driving, which in turn increases the quantity of driving.
• The calculator uses 2019 lane mileage and VMT data from the Federal Highway Administration (FHWA) and limits its geographic application to Class 1 roadways in US Metropolitan Statistical Areas (MSAs) or Class 2 or 3 roadways in urbanized counties.
• To account for uncertainty and avoid false precision, induced VMT results are reported in confidence intervals of +/-20%.
• Cumulative greenhouse gas (GHG) emissions are projected through 2050 under two scenarios: a business-as-usual (BAU) case and an NDC-aligned case. The NDC-aligned case assumes 100% electrification of new passenger vehicles by 2035 and rapid renewable power development.
• The lifecycle emissions calculation includes direct emissions from gasoline and diesel combustion, as well as upstream emissions from fuel production and manufacturing emissions for light-duty vehicles.

APA

RMI (n.d.). SHIFT Calculator - Methodology. https://rmi.org/app/uploads/2021/10/rmi_shift_calculator_methodology.pdf

Chicago

RMI. SHIFT Calculator - Methodology. n.d. https://rmi.org/app/uploads/2021/10/rmi_shift_calculator_methodology.pdf.

Wikipedia

{{cite report |author=RMI |title=SHIFT Calculator - Methodology |url=https://rmi.org/app/uploads/2021/10/rmi_shift_calculator_methodology.pdf |access-date=23 October 2026 |via=Climate Insights Directory}}

BibTeX

@techreport{rmindshift, author = {{RMI}}, title = {{SHIFT Calculator - Methodology}}, institution = {RMI}, url = {https://rmi.org/app/uploads/2021/10/rmi_shift_calculator_methodology.pdf}, urldate = {2026-10-23}, note = {Indexed by Climate Insights Directory} }