Data Updates Completed in the NCST Induced Travel Calculator

The National Center for Sustainable Transportation (NCST) Induced Travel Calculator, an important tool for induced VMT analyses, has been updated with newer data. In collaboration with Caltrans DRISI, the UC-Davis team that developed the calculator has updated HPMS data for the years 2017, 2018 and 2019. Previously, only 2016 data could be utilized in the on-line calculator. Users can now select one of the four years of data when making their analysis selections.   


This update will allow Caltrans teams to use more recent data in applicable project-specific induced VMT calculator estimates. This is important, as relevant Caltrans guidance – the Transportation Analysis Framework – includes the NCST calculator as one approach to estimate Induced VMT for State Highway System capacity projects for California Environmental Quality Act analyses.    


The integration of the updated data into the calculator completes a key component of the current Caltrans-sponsored research project to update calculator data and examine possible future improvements to the calculator. The calculator is available on-line at:


On a related topic, due to interest in other states, a national version of the NCST calculator is  now available. The Rocky Mountain Institute in Colorado, in collaboration with NCST and others, have compiled lane-mile and VMT data for the rest of the country and built a national induced travel calculator based on NCST’s California calculator. The national calculator also provides estimates of the GHG emissions associated with induced VMT. The national calculator is available at: