Agenda - Public Works Committee - 03/21/2023

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V2 4.101* proposed — 0.01*X (15 * Rproposed proposed e- CMF = y2 4.101*existsisting - 0.01 x X e 15 Rex7tg existing Vproposed = proposed posted speed limit (mph) Rproposed = proposed horizontal curve radius (ft) Rproposed= proposed curve superelevation (degrees) Vexisting = existing speed limit (mph) Rexisting = existing horizontal curve radius (ft) Xexisting = existing curve superelevation (degrees) CMFs are used to estimate safety performance after implementation of an improvement by multiplying the CMF with the historical crash rate to compute the estimated future crash rate. Future Year Capacity Analysis A year 2040 intersection capacity analysis was completed to evaluate how the study intersections are expected to operate in the future when the roundabout concepts are implemented. The operational analysis for the roundabout concepts was performed using RODEL. RODEL is a software program that is based on existing roundabout operational research and uses an empirical formula method to determine roundabout delay based on geometric features and traffic flows. RODEL results for a Confidence Level (CL) of 50 percent were determined, which is typically used for roundabout analysis and is considered comparable to other analysis software. The results of the roundabout operational analysis for Year 2040 forecast conditions is shown in Table 14. For the roundabout operational analysis, all RODEL models were built as the roundabouts were designed in the intersection improvement concepts shown in Figure 5 to Figure 10. Table 14: Year 2040 Roundabout Operations Analysis AM Peak PM Peak LOS Delay (sec.) LOS Delay (sec.) Intersecting Roadway 167th Ave Ramsey Blvd (CSAH 56) Sunwood Dr Operations analysis results for future year conditions indicate the roundabout control alternatives operate at acceptable levels of service. 25