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I-74 Corridor Ramp Metering

I-74 Corridor Ramp Metering. Green Township Trustee Meeting May 24, 2004. Statewide Safety & Congestion Initiative. Statewide Historical Crashes. The New Highway Safety Program. Safety “Hot Spots” Defined by crash frequency Targets Urban freeways Highway Safety Program

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I-74 Corridor Ramp Metering

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  1. I-74 Corridor Ramp Metering Green Township Trustee Meeting May 24, 2004

  2. Statewide Safety & Congestion Initiative

  3. Statewide Historical Crashes

  4. The New Highway Safety Program • Safety “Hot Spots” • Defined by crash frequency • Targets Urban freeways • Highway Safety Program • Defined crash rate, frequency, severity, etc. • Targets Rural freeways and non-freeways • Targets Urban freeways and non-freeways

  5. GOALS • Established Crash Reduction Goals • Continual improvement in crash reduction • By 2008, 1.00 fatalities per 100 MVMT • By 2015, 10% reduction in the total number of crashes (40,000) • By 2015, 25% reduction in the total number of rear end crashes (25,000)

  6. What are Ramp Meters? • Traffic signal on an entrance ramp to a freeway • Release one or two vehicles at a time • Break up long platoons of merging vehicles

  7. Operations • Balance Side Street Demand • Cycle Length • 4 to 15 seconds • Multi-Lane Ramp • One or two vehicles per green • Staggered-metering • Time-of-Day or Demand Responsive • Queue Detection • Demand & Passage Detection • Merge Detection • Mainline Detection

  8. What Ramp Meters Can Do? • Realized Benefits • Reduce crashes by 15-50% • Improve travel speeds by 8-60% • Provide more uniform traffic flow

  9. Nationally • More than 33 US metro areas • Started in Chicago & Detroit in 1960s • Case Studies • Twin Cities • Madison

  10. Twin Cities – Case Study • Without Ramp Meters • 9% reduction in freeway volume • 22% increase in freeway travel times • 91% reduction in reliability of travel time • 26% increase in crashes • Support for meters increased from 60% to 70% • Benefit/cost = 15:1 • Use faster cycle times / fewer meters

  11. Madison – Case Study • 5 Ramp Meters Deployed • Preliminary Results • Reduced Crashes – 50% • Especially Rear-ends • Improved Highway Throughput – 30% • High Driver Compliance - 96% • Reduced Speed Variability • Some Travel Time Increase • Traffic diversion Was Not Observed • Public Acceptance • 92% - improved safety

  12. Concerns… • Aren’t signals at ramps already metering? • Ramp signals operate differently • Ramp signal allow many (15 to 20) vehicles to enter the freeway at once. • Ramp meter only allow one or two vehicles to enter at once. • Is I-74 bad enough yet? • ODOT’s HSP and Hot Spot list • Approximately 850 crashes (2000-2002) on the corridor with approximately 575 eastbound crashes • Travel speed are low during the morning peak hour

  13. Concerns… • Will the ramp meter backup traffic on surface streets? • Ramp meter will not exacerbate the queuing problem • Why install ramp meters on I-74 1st? • Safety Program identified the problem – ramp meters were a potential medium cost solution. • ODOT developed a statewide ramp metering protocol. • More to come in all areas of the state.

  14. Schedule Public Meeting Steering Committee Meeting

  15. Conclusions • Ramp Meters improve safety • Ramp Meters increase traffic flow • Ramp Meters will not exacerbate surfacing street queuing • Additional Technical Studies • Public Outreach • Driver Survey Next Steps

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