NREL OpenPATH: Open Platform for Agile Trip Heuristics

OpenPATH logo

NREL's Open Platform for Agile Trip Heuristics (NREL OpenPATH) enables people to track their travel modes—by car, bus, bike, walking, etc.—and measure their associated energy use and carbon footprint.

Formerly known as e-mission, the NREL OpenPATH tool features continuous data collection and analysis via a smart phone app backed by a server and automated data processing. Its open nature enables transparent data collection and analysis while allowing for continuous improvement coupled with accessibility and adaptability by others.

NREL OpenPATH empowers communities to collect and understand their own travel data while achieving place-based, locally relevant sustainable mobility goals.

Access and Use NREL OpenPATH


NREL OpenPATH is fully open-source software.

Clone or fork from GitHub.


We offer free and paid options for public agencies and universities.

Use NREL-hosted version.

Study Participants 

For NREL OpenPATH studies, we have installation instructions and FAQs.

Follow participant guidelines.

Key Capabilities

  • Creates end-to-end multi-modal trip diaries using sensed data; sensed data turns on and off automatically to avoid draining the phone battery
  • Enables automated mode detection and trip and section segmentation
  • Enables automated or customized trip labeling
  • Enables users to mark the quality of the infrastructure along their routes (e.g., to report near-miss incidents)
  • Enables user surveys based on individualized travel patterns
  • Public dashboard functionality (e.g., CanBikeCO) allows for multi-metric program comparisons
  • Deployer dashboard functionality enables program administrators to conduct real-time program monitoring

Example Uses

Travel Surveys

NREL OpenPATH enables researchers, municipalities, and other groups to conduct travel surveys. A few examples include surveys conducted in:

  • Richmond, California, by the Center for Community Innovation at the University of California, Berkley, to better understand the travel patterns of low-income households and assess the impact of gentrification
  • Asuncion, Paraguay, by the Department of Urban Planning at the University of California, Berkley, to collect data on travel patterns and inform a regional travel-demand model
  • Sydney, Australia, by the University of New South Wales to understand changes in essential worker travel behavior.

Program Evaluation Support

NREL OpenPATH can also be used to monitor and evaluate mobility programs.

A recent example involves the Colorado Energy Office's Can Do Colorado E-Bike Pilot Program. NREL developed a customized version of the tool—called CanBikeCO—to determine how giving frontline workers an e-bike mobility option would affect their travel behavior, possibly contributing to a longer-term shift away from car dependence.

As part of an initial, small-scale pilot program, 12 low-income essential workers in the Denver area used the tool for 3 months, leading to the collection of a unique data set consisting of partially automated travel diaries, combining sensed and surveyed data with geographic information. The insights garnered from the small-scale pilot informed the design of the full-scale, 2-year pilot launched in 2021 in locations across Colorado. For more information, refer to the news article Pilot Program Sheds Light on E-Bike Use Patterns, Energy-Efficiency Benefits.


NREL's K. Shankari developed the original version of the tool as part of a research project at the University of California, Berkeley, in association with its Buildings, Energy, and Transportation Systems group. Other organizations have also contributed to the development of the open-source platform: the German Research Centre for Artificial Intelligence (modified summary screen), University of Washington's Center for Accessible Technology (improved app's accessibility), and University of New South Wales (created deployer dashboard).


The following publication provides detailed information about NREL OpenPATH. For NREL's full collection of related documents, visit the Publications Database.

The CanBikeCO Mini Pilot: Preliminary Results and Lessons Learned, NREL Technical Report (2021)

e-mission: An Open-Source, Extensible Platform for Human Mobility Systems, University of California at Berkeley Technical Report (2019)

e-mission: An Open-Source, Smartphone Platform for Collecting Human Travel Data, Transportation Research Record: Journal of the Transportation Research Board (2018)


To discuss your partnership interests, explore opportunities for using NREL OpenPATH to collect opt-in travel-behavior data, or learn about our custom analyses and related resources, please contact us.

K. Shankari

Postdoctoral Researcher, Director's Fellow