Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types Erik Ruehr, VRPA Technologies, Inc. ITE Western District Annual Meeting June 26, 2012

Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types Photo: Casey Bergh Sample Roundabout

Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types Outline Introduction History of Roundabout Capacity Analysis Tools 2010 HCM Roundabout Procedure Level of Service Versus Delay Tables Implications for Comparisons to Other Intersection Types Non-Yielding Right Turn Bypasses Conclusion

Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types Introduction Two-Way Stop Control All-Way Stop Control Traffic Signal Roundabout TYPES OF AT-GRADE INTERSECTIONS

Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types History of Roundabout Capacity Analysis Tools 2000 Highway Capacity Manual: Initial Guidance 2010 Highway Capacity Manual: Full Procedure Sidra Rodel Traffic Simulation

Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types 2010 HCM Roundabout Procedure Incorporates NCHRP Report 572 Methodologies (with Enhancements and Extensions) Lane-by-lane Analysis of Single-lane and Multi-lane Roundabouts Produces Level of Service and Delay Results

Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types Level of Service Versus Delay Tables Two-Way Stop / All-Way Stop Traffic Signal < < > > > > >80

Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types Level of Service Versus Delay Tables Two-Way Stop / All-Way Stop / Roundabout Traffic Signal < < > > > > >80

Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types Implications for Comparisons to Other Intersection Types Two-Way Stop –Major Street Through/Right Movements Have Zero Delay All-Way Stop –Similar to Roundabout Traffic Signal –Comparable Based on Level of Service Per 2010 HCM Definitions –Be Aware of Differences in Delay Versus Level of Service Tables –Non-Yielding Bypass Lanes and Free Right Turn Lane Comparisons

Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types Non-Yielding Right Turn Bypasses and Free Right Turns Non-Yielding Right Turn Bypass Free Right Turn Lane (Included in Overall Intersection Delay Calculation) (Not Included in Overall Intersection Delay Calculation)

Roundabout Level of Service and Delay and Comparison to Other Intersection Types Roundabout Level of Service and Delay and Comparison to Other Intersection Types Conclusion 2010 Highway Capacity Manual Includes Complete Procedure for Roundabouts Comparisons of Roundabouts to Other Intersections Can Be Complicated Comparisons Based on Level of Service Are More Consistent Than Comparisons Based on Delay