This calculator allows users to estimate the VMT induced annually as a result of adding general-purpose lane miles, high-occupancy vehicle (HOV) lane miles, or high-occupancy toll (HOT) lane miles to publicly owned roadways, like those managed by the California Department of Transportation (Caltrans), in one of California’s urbanized counties (counties within a metropolitan statistical area (MSA)). The calculator applies only to facilities with Federal Highway Administration (FHWA) functional classifications of 1, 2 or 3. That corresponds to interstate highways (class 1), other freeways and expressways (class 2), and other principal arterials (class 3).
To obtain an induced VMT estimate for a roadway capacity expansion project, enter the project length (in lane miles added), the geography (MSA for additions to interstates; county for additions to other Caltrans-managed class 2 or 3 facilities), and the base year (2016, 2017, 2018, or 2019). The base year indicates which year of VMT and lane mile data will be used to estimate the induced VMT.
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