Highway Capacity Manual Methodologies for Corridors Involving Freeways and Surface Streets (2020)

Below is the uncorrected machine-read text of this chapter, intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text of each book. Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.

- iv - TABLE OF CONTENTS SUMMARY ............................................................................................................................................... 1 1. INTRODUCTION ............................................................................................................................. 3 2. LITERATURE REVIEW ................................................................................................................ 4 3. CRITICAL REVIEW OF THE HCM .......................................................................................... 8 4. PERFORMANCE MEASURES .................................................................................................. 12 5. QUEUE SPILLBACK INTO FREEWAYS .............................................................................. 14 6. QUEUE SPILLBACK INTO URBAN STREETS ................................................................... 27 7. LANE-BY-LANE SPEED AND FLOW ESTIMATION METHODS FOR FREEWAYS .................................................................................................... 35 8. SYSTEM ANALYSIS ..................................................................................................................... 41 9. SOFTWARE IMPLEMENTATION .......................................................................................... 43 10. CONCLUSIONS AND RECOMMENDATIONS .................................................................... 43 REFERENCES ....................................................................................................................................... 45 APPENDIX A. CHAPTER 38: SYSTEM ANALYSES .......................................................... 47 APPENDIX B. OFF-RAMP QUEUE SPILLBACK.............................................................. 232 APPENDIX C. FREEWAY OFF-RAMP – QUEUE SPILLBACK ANALYSIS ................ 245 APPENDIX D. ON-RAMP QUEUE SPILLBACK CHECK ................................................ 293 APPENDIX E. ON-RAMP QUEUE SPILLBACK ANALYSIS .......................................... 304 APPENDIX F. FREEWAY FACILITIES LANE-BY-LANE ANALYSIS ......................... 351 APPENDIX G. GLOSSARY .................................................................................................... 378

- v - LIST OF FIGURES Figure 1 – HCM service measures by system element and mode .................................................. 8 Figure 2 – Schematic of a diverge influence area (HCM) .............................................................. 9 Figure 3 – Recommended performance measure framework for different evaluation purposes ..................................................................................................... 13 Figure 4 – Data collection framework for queue spillback into freeway facilities ....................... 15 Figure 5 – Survey for off-ramp queue spillback study sites – outcome by state .......................... 16 Figure 6 – Miami, FL – I-95 SB to SW 25th Rd. .......................................................................... 17 Figure 7 – Tampa, FL – I-275 NB to SR-60 ................................................................................. 17 Figure 8 – Norfolk, VA – I-64 WB to Northampton Blvd ........................................................... 18 Figure 9 – Centreville, VA – I-66 WB to SR-28 (Sully Rd) ........................................................ 18 Figure 10 – Centreville, VA – I-66 EB to SR-28 (Sully Rd) ........................................................ 18 Figure 11 – Minneapolis, MN – I-35W SB to 35th St. ................................................................. 18 Figure 12 – Atlanta, GA – I-285 NB to I-20................................................................................. 19 Figure 13 – Miami, FL – I-75 SB to SR 826 ................................................................................ 19 Figure 14 – Atlanta, GA – I-285 NB to GA-141 .......................................................................... 19 Figure 15 – Sacramento, CA – SR-99 NB to SR-50..................................................................... 19 Figure 16 – Back-of-queue length measurement – off-ramp queue spillback .............................. 20 Figure 17 – Sample of data illustrating queue spillback: (a) queue length and (b) speeds by lane ..................................................................................... 21 Figure 18 – Unbalanced lane usage at the off-ramp: (a) right lane and (b) left lane .................... 22 Figure 19 – Effects of queue spillback across freeway lanes at three locations upstream of the exit experiencing spillback (I-275 EB – Tampa, FL) ...................................... 22 Figure 20 – Blockage of one (a) or two (b) mainline lanes due to off-ramp queue spillback ...... 23 Figure 21 – Example of a forced merging maneuver for a vehicle attempting to join the off-ramp queue .............................................................................................................. 24 Figure 22 – Micro-simulated off-ramp queue spillback (I-105@Bellflower Interchange – Los Angeles, CA) ................................................................................................ 24 Figure 23 – Procedure for identifying spillback occurrence at an off-ramp/weaving segment .... 25 Figure 24 – Expanded link-node structure to evaluate the off-ramp segment .............................. 26 Figure 25 – Data collection framework for queue spillback into urban streets (signalized intersection) ............................................................................................................. 27 Figure 26 – I-285 NB @ South Cobb Dr. and affected movements by on-ramp queue spillback: (a) NB-Th/R and (b) SB-L ......................................................................................................... 30 Figure 27 – I-285W SB @ Cobb Pwky Dr. and affected movements by on-ramp queue spillback: (a) NB-L and (b) SB-Th/R .............................................................................. 31 Figure 28 – I-285W NB @Cobb Pkwy Dr. with NB-R movement affected by on-ramp queue spillback ............................................................................................................ 31 Figure 29 – Friars Rd. @ I-15 NB with WB-R movement affected by on-ramp queue spillback........................................................................................................................... 32 Figure 30 – Partial blockage of northbound through movement by vehicles trapped inside the intersection box ............................................................................................ 33 Figure 31 – Procedure for identifying spillback occurrence at an on-ramp ................................. 35

- vi - Figure 32 – Comparison of lane flow distribution on two different 2-lane segments: (a) Minneapolis, MN and (b) Salt Lake City, UT ...................................................................... 37 Figure 33 – Comparison of lane flow distribution on two different 3-lane segments: (a) Tampa, FL and (b) St. Paul, MN ......................................................................... 38 Figure 34 – Comparison of lane flow distribution on two different 4-lane segments: (a) Salt Lake City, UT and (b) Tampa, FL ............................................................... 39 Figure 35 – Field data and predicted speed-flow curve for (a) lane 1 and (b) lane 2 (CA-1 NB – Santa Cruz, CA) .................................................................................... 41 Figure 36 – Origins and destinations for a sample network (Gainesville, FL) ............................. 42