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[DRAFT] Intersection Control Evaluation SRF Consulting Group, Inc. County Road E at Snelling Ave N (CR 76) 10 November 30, 2021 Safety Analysis A safety analysis was performed to estimate the number of crashes per year for each traffic control alternative for the Opening Year 2023 and Forecast Year 2043 conditions for the study intersection. For the all-way stop control alternative, crash rates were expected to match the existing observed crash rate. To analyze the crash rates for the traffic signal and roundabout alternatives, Crash Modification Factors (CMF) were taken from the CMF Clearinghouse. The CMF clearinghouse is a database sponsored by the Federal Highway Administration and contains CMFs determined through research studies. These CMFs can be used to estimate the impact that a road or intersection improvement will have on the expected crash rate for that location. A summary of the projected crashes per intersection alternative is shown in Table 9. Table 9. Crash Analysis Results Alternative Intersection ADT Crash Modification Factor Average Crash Rate (1) Projected Crashes/Year Opening Year 2023 Forecast Year 2043 Opening Year 2023 Forecast Year 2043 All-Way Stop Control 11,880 13,050 N/A 0.24 (2) 1.04 1.14 Traffic Signal Control 0.95 0.22 (3) 0.95 1.05 Roundabout Control (single-lane) 1.03 0.24 (3) 1.04 1.14 (1) Per 100 million entering vehicles (2015-2019 data). (2) Assumed to match the observed crash rate. (3) Based on the adjusted crash modification factor (CMF). Based on the results of the crash analysis, the three alternative controls are anticipated to have a similar number of crashes per year. However, most crashes at roundabouts occur at lower speeds and shallow angles due to the geometry of a roundabout. With lower speeds, the severity of the crashes is typically decreased. A roundabout virtually eliminates right-angle and left-turn head-on crashes; this is particularly true with single-lane roundabouts. Planning-Level Cost Analysis Capital Costs Since the study intersection currently exists as an all-way stop-controlled intersection, costs associated with the all-way stop control are anticipated to be minimal. Based on preliminary concepts, additional right-of-way is not anticipated to be required for either the traffic signal or roundabout. The cost to construct a signal at the intersection is estimated to be between $300,000 and $400,000, while the cost to construct a roundabout is estimated to be between $1,200,000 and $1,500,000. Operation and Maintenance Costs Traffic signals typically have higher operation and maintenance costs because of the electricity required to operate the signal and routine maintenance required to keep the signal in operation, such as retiming