We have posted a brief video tutorial to the DEP Resources Page to assist DEP API users with finding data dictionaries and other supplemental documentation. Even though this documentation has always been available to our API users, we’re responding to feedback that the documentation can be difficult to find. In response, we have upgraded the API documentation, data dictionaries, and supplemental information to make them easier to find and use. Our video tutorial describes how to access each API data dictionary.

Note: for security reasons, we don’t grant open access to data dictionaries to the general public. API documentation is ONLY available for users who already have a RITIS login account and approval for accessing DEP data. Users only have access to the dictionaries and supplemental documents associated with data they have permission to request. Please contact dep-support@ritis.org if you have questions or need further assistance.

On March 9, 2026, the VDOT RWIS data set was expanded to provide many additional fields.  Special thanks go out to the VDOT and Vaisala teams for their assistance in making this possible. Updated information on RWIS output fields is available in the /rm3p/weather endpoint section of the API Documentation page. Additional guidance on how to access API documentation and data dictionaries will be provided in an upcoming announcement.

On February 13, 2026, the DEP API was updated to include parking occupancy profiles for VDOT Parking Data. This appears as a new element in VDOT Parking Data API feed. The data is generated by VDOT based on periodic parking lot usage counts.

On January 9th, 2026, the DEP API added per-lane detector data to the historical detector endpoint. Lane data is now returned as part of the regular request, and is available to all DEP API users.

We are working closely with Virginia Railway Express (VRE) to resolve ongoing issues with parking data. VRE is actively working on hardware replacement and system updates across several parking lots. If you see ongoing issues with the DEP, please report them to DEP support at dep-support@ritis.org.

On November 14, 2025, DEP API was updated to use SmarterRoads as the source of VDOT RWIS data in response to VDOT’s migration of RWIS stations described in November 6th announcement. The DEP development team switched the source interface in a way that preserved the DEP API output and prevented need for any rework from the downstream users. VDOT has confirmed that the element mappings and units are correct. As of November 14, 2025, VDOT RWIS data is once again available in the DEP API output.