The purpose of this project was to estimate regionalized safety performance functions (SPFs) for urban and suburban collector roads and at-grade intersections using roadway inventory and crash data from state-owned roadways in Pennsylvania. Five years of crash data (2013-2017) were appended to traffic volume and roadway and roadside features in order to estimate statistical models of total and fatal + injury crash frequency. SPFs were developed for two-lane undivided roadway segments and the following at-grade intersections types: three-leg intersections with stop-control on the minor approach; three-leg intersections with all-way stop control; four-leg intersections with stop-control on the minor approach, four-leg intersections with all-way stop control; and four-leg signalized intersections. Based on the regionalization process, engineering district-level SPFs with county-leveladjustments were recommended for two-lane undivided roadway segments. Statewide SPFs were recommended for three-leg all-way stop controlled, four-leg minor-street stop-controlled, four-leg all-way stop-controlled and four-leg signalized intersections. Statewide SPFs with district-level adjustments were recommended for three-leg minor-street stop-controlled intersections. The full report is available online at http://www.dot7.state.pa.us/BPR_PDF_FILES/Documents/Research/Complete%20Projects/Operations/Regionalized_Urbansuburban_Collector_Road_Safety_Performance_Functions.pdf