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Bay Area Ramp Metering

Bay Area Ramp Metering. Bay Area Arterial Operations Committee November 18, 2008 Jeff Georgevich, MTC. Outline. Ramp Metering Basics Issues (Real and Imagined) Recent Ramp Metering Projects Future of Ramp Metering in the Bay Area. Ramp Metering Basics.

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Bay Area Ramp Metering

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  1. Bay Area Ramp Metering Bay Area Arterial Operations Committee November 18, 2008 Jeff Georgevich, MTC

  2. Outline • Ramp Metering Basics • Issues (Real and Imagined) • Recent Ramp Metering Projects • Future of Ramp Metering in the Bay Area

  3. Ramp Metering Basics • Goal: Provide faster and more reliable travel time in corridor (freeway & arterials) • How: Control rate at which vehicles enter freeway • Passive Metering – break up platoons • Restrictive Metering – freeway V/C < 1.0 • Measures of Effectiveness • Maximize freeway throughput • Minimize travel time (freeway + ramp) • Minimize impact on arterials

  4. Types of Ramp Metering • Pre-set or Non-traffic Responsive • Fixed rates by Time of Day (TOD) • Not based on conditions on mainline • Traffic Responsive or Adaptive • Meter rates based on freeway mainline occupancy or flow • Queue detector at top of onramp • Most typically used by Caltrans District 4.

  5. Types of Ramp Metering, cont • Central Control or Corridor Metering • Central computer sets rate at multiple ramps to optimize flow in corridor • Algorithms (ALINEA, SWARM, etc.) • Cutting edge, not widely deployed yet, hard to model operation and benefits

  6. Issues (Real & Imagined) • Diversion onto Arterials • Congestion near On-Ramp • Equity/Benefits for Longer Trips • Mode Shift/Encourages SOV • Public Perception/Satisfaction • Safety • Environmental Factors

  7. Recent Projects • Minneapolis, MN • EB Ala-580/Pleasanton (Tri-Valley #1) • San Mateo 101 • EB Ala-580/Livermore (Tri-Valley #2) • WB Ala-580 (Tri-Valley #3)

  8. Minneapolis, MN • Legislature required study of effectiveness • Fall 2000 – shut down existing • Volume/Throughput: plus 9% (14% peak) • No significant change on arterials • Travel Time: lower with ramp meters • Without meters, more unpredictable • Safety: 26% fewer crashes with meters • Air Quality: Meters reduce emissions

  9. EB Ala-580/Pleasanton • Meter 3 Eastbound onramps on I-580, east of I-680 • Major Issue: cut-through traffic on local streets entering I-580 at Santa Rita • Restrict on-ramp volume • Activate Ramp Meters and open Auxiliary Lane (Santa Rita to El Charro)

  10. EB Ala-580/Pleasanton, cont

  11. EB Ala-580/Pleasanton, cont • Metering Implemented June 2003 • Santa Rita set at 40% of ‘before’ volume • Results – Freeway in Metered Section • Mainline Volume increased 8% • Travel time decrease 20% (2-7 pm) and 60% in peak (4-6 pm) • Corridor-wide (Foothill to Altamont Pass) • Volume: +2.5%, Travel time: -2.5% • shifted bottleneck to Altamont Pass

  12. EB Ala-580/Pleasanton, cont • Results – Arterial Cut-through Routes • Increased congestion on approaches to Santa Rita onramp • Reduced volume and travel time on cut-through routes • Overall: increased freeway volume and speed, and decreased cut-through traffic

  13. San Mateo 101 • Meter SM-101, Rte 92 to SCl Co • Meters set at demand rate • 8 Interchanges (Willow Rd not completed) in early 2007 • Early Results - Freeway • NB: no major effect due to Rte 101/92 • SB: reduced congestion by 1 hour (AM & PM) and reduced travel time by 10 minutes (30%)

  14. San Mateo 101, cont • Early Results – Arterials • LOS got worse at 5 I/S, and better at 3 I/S • Total I/S volume change over 10%: 5 increased and 4 decreased • Roadway segment: volume change over 10%: 7 increased, 4 decreased • Based on limited impacts, proposed “6-month after” evaluation of arterials dropped by locals

  15. EB Ala-580/Livermore • Meter Foothill and 6 EB I/Cs in Livermore • Foothill is west of I-680 • Expand EB metering to 10 I/Cs (13 miles) • Results – Freeway • Volume fluctuated, but generally higher • In peak hour, 2% increase through bottleneck • Travel time decreased by 32% (10 minutes)

  16. EB Ala-580/Livermore, cont • Results – Arterials • Lower volume on cut-through routes • Few onramp queues extended beyond ramp

  17. WB Ala-580/Tri-Valley • WB AM Metering, Grant Line Rd to Foothill • Restrictive metering at Airway (bottleneck) • Implement Sept 2008 • Preliminary Results • Free flow speed from I-205 to I-680 • Lower volume at Airway Blvd

  18. Future of Ramp Metering • Activate existing meters in Santa Clara • Routes 85, 87, and 101, by end of FY 08/09 • CMIA Projects include TOS and Meters • Freeway Capacity Projects • MTC Policy: Include TOS and ramp meters • FPI - $625 million for TOS/RM in T-2035 • Front load construction

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