SPCC Segmentation Support

This document outlines the process for generating generalized roadway segments and associated smoothed SPCC segment designations from a small set of smaller roadway segments. The process involves two major components. First, a programmatic approach with professional judgement and adjustments is used to pre-process segments to develop logical generalized roadway segments. Next, these generalized segments are used as inputs into the SPCC segment smoothing tool to develop new final smoothed segment SPCC assignments.

Part 1: Developin Generlized Roadway Segmentation

Developing Segmentation

1. Associate Street Name
   • Most likely street names are assigned to roadway segments using the OpenStreetMap (OSM) database of streets.
2. Segment Grouping & Splitting
   • Segments are grouped based on their street name and facility type fields.
   • Long roadway segments were split at census tract boundaries, which serve as a proxy for logical geographic segments.
3. Manual Review and Adjustments
   • All resulting segments were reviewed, and professional judgment was applied to refine segmentation results.

Mapping Inputs and Segmentization

Below is a map depicting the segmentation input and output:

• Original Segments: Shown as narrow lines, with “color_index” representing the original segment identifier.
• Clustered Segments: Represented by thicker lines, “rp_index_id” represents the new unique cluster identifier.

`summarise()` has grouped output by 'SID_', 'SID'. You can override using the
`.groups` argument.

Part 2: Applying SPCC Segment Smoothing Tool

Using the refined segments, the SPCC segment smoothing tool is applied using the final SPCC 2.0 land use layers to developing the final resulting smoothed segment values. See SPCC documentation for documentation on running SPCC tools.