Street Network Analysis

Transportation.Roads is the recommended starting point for almost anything related to Utah street centerlines. This includes cartography, address location, and, now, network analysis. (It is also worth mentioning that the UDOT linear referencing system is derived from attributes in this dataset).

While data used to support network analysis has many potential parameters, at a basic level, two components are especially important: 1) connectivity and 2) impedance (i.e. travel speed/costs).

Connectivity of centerline features in Transportation.Roads is actively maintained but an impedance measure, while planned for later this year, has not been actively enforced to date. However, it is possible to use a combination of cartographic feature codes (CFCC field), spatial queries, and the existing values in the SPD_LMT field to create a relatively crude but effective representation of speed limits that, then, can be used as an input to an impedance measure.

Important Fields:

• F_T_IMP_MIN Impedance, estimated in minutes in direction of line's orientation.
• T_F_IMP_MIN Impedance, estimated in minutes in the opposite direction of line's orientation.

In areas where surface streets are likely to encounter traffic controls at intersections and other congestion, travel time has been increased by a factor of 1.3 (this will be 1.5 in future datasets). Otherwise the approximate speed limit was used to estimate travel time.

There are no constraints or warranties with regard to the use of this dataset.

Comments, questions, compliments, or concerns can be directed to Greg Bunce from AGRC at GBunce@utah.gov or 801-349-0039.

The multimodal network dataset is a product of a 2018 FHWA grant. The project, led by UDOT, was a pilot for measuring multimodal network connectivity. Other partners included WFRC, MAG, and AGRC.

This dataset is built using SGID Roads, Trails, and UTA Transit (light-rail and commuter rail) data, as well as 2019 GTFS transit routes and stops. In addition, ‘connector’ lines are created during the build process to provide the needed junctions.

Currently, the dataset is limited to the Wasatch Front region (Box Elder, Davis, Salt Lake, Utah, and Weber county). Furthermore, as part of the scope of the project, 50 sites were chosen where the data is optimized for multimodal connectivity (particularly the bike and pedestrian modes of travel). Pedestrian data was densified within .5 miles of the sites and bike data was densified within 1 mile of the sites. In other words, your mileage may vary when you venture beyond these zones.

The multimodal network dataset will be updated in conjunction with SGID Road updates.

Also, here is some general information on building travel sheds in ArcMap using this dataset and Network Analyst.

Please visit this project’s GitHub repository to learn more about (or contribute to) the build process.

We hope to continue the project and expand the multimodal footprint beyond these original 50 sites. Please get in contact with us if you are interested in contributing or playing a role.

Comments, questions, compliments, or concerns can be directed to Greg Bunce from AGRC at GBunce@utah.gov or 801-349-0039.