Interchange Design To Accommodate Ramp Metering System

US Transportation Collection2020PDFTech ReportWashburn, Scott S.Shastri, AkhileshCenturion, ArielUniversity of Florida. Transportation InstituteFlorida. Department of TransportationUniversity of Florida. Transportation InstituteUnited StatesFreeway operationsGuidelinesHighway designRamp meteringRamps (Interchanges)Freeway interchange designFDOT Contract BDV31-977-92Final Report Feb. 2018-Dec. 2020The majority of the existing research regarding ramp metering has largely been focused on ramp signal timing algorithms and/or the design of the on-ramp itself for accommodating ramp metering operations, irrespective of the particular overall interchange design. However, what is generally lacking is research that considers how ramp metering should factor into the selection of an overall interchange configuration. The objective of this project was to develop guidance on interchange design, with consideration of ramp metering, that is appropriate for a planning and preliminary engineering level. In other words, guidance is provided to help understand the impact of ramp metering on interchange operations across a variety of interchange designs. Detailed operational questions (e.g., signal phasing sequences, signal coordination settings amongst the ramp terminal and adjacent intersections, the type of ramp-metering control algorithm, interactions between adjacent interchanges, and similar) are beyond the scope of the guidance developed from this project. Specific topics addressed in this report include: ramp meter to freeway merge acceleration distance, multilane metering, performance measures, interchange configuration factors, and macroscopic queuing analysis. The conclusions and recommendations from this study are intended for incorporation into the FDOT Interchange Access Request User\u2019s Guide.125