AN ANALYSIS OF SHORT TERM IMPLEMENTATION OF RAMP CONTROL ON THE DAN RYAN EXPRESSWAY, JULY 1967

A SHORT-TERM IMPLEMENTATION OF ENTRANCE RAMP CONTROL WAS MADE ON THE NORTHBOUND DAN RYAN EXPRESSWAY IN ORDER TO GAIN ADDITIONAL KNOWLEDGE OF THE RELATIVE INFLUENCE THAT VARIOUS CORRIDOR ELEMENTS HAVE UPON RAMP CONTROL. AN INTERPLAY BETWEEN THE EXPRESSWAY AND FRONTAGE STREET RESULTED IN THE GENERATION OF EXCEEDINGLY HIGH ENTRANCE RAMP DEMANDS (1370 VPH) AT THE POINT WHERE THE EXPRESSWAY CURVES AWAY FROM THE FRONTAGE STREET. CONGESTION WAS TRIGGERED AND SUSTAINED BY THIS RAMP TRAFFIC OVERLOADING THE EXPRESSWAY MERGING SECTION. MANUALLY OPERATED PORTABLE RAMP METERING EQUIPMENT WAS USED ON FOUR SUCCESSIVE ENTRANCE RAMPS TO ADJUST THE MERGE DEMANDS TO A LEVEL WHICH COULD ACCOMMODATED WITHOUT SEVERE ADVERSE EFFECTS ON THE EXPRESSWAY. THE CONTROL PLAN RESULTED IN CONSIDERABLE TIME SAVINGS FOR EXPRESSWAY MOTORISTS BY DECREASING THE SEVERITY AND DURATION OF CONGESTED OPERATIONS. DELAYS INCURRED WERE AT THE EXPENSE OF VEHICLES WAITING IN QUEUES AT THE CONTROLLED RAMPS. THERE WAS NEGLIGIBLE DELAY TO SURFACE STREET TRAFFIC IN THE CORRIDOR ALTHOUGH DIVERSION FROM THE METERED RAMPS WAS QUITE SIZEABLE. THIS INITIAL STUDY POINTED OUT THE NEED TO EXTEND CONTROL TO ADDITIONAL UPSTREAM RAMPS AND TO ADJUST THE LEVEL OF CONTROL ON A TRAFFIC-ACTUATED BASIS IN ORDER TO FURTHER IMPROVE EXPRESSWAY OPERATIONS. /AUTHOR/

• Supplemental Notes:
  • Hpr, Study IDENT NO IHR-88, BPR NO 4522-204
• Corporate Authors:

  Illinois Department of Transportation

  Division of Highways, 2300 South Dirksen Parkway
  Springfield, IL  United States  62764

  Bureau of Public Roads /US

  400 7th Street, SW
  Washington, DC  United States  20590
• Authors:
  • Fonda, R D
• Publication Date: 0

Subject/Index Terms

• TRT Terms: Actuated traffic signal controllers; Control; Expressways; Frontage roads; Interchange ramps; Merging traffic; Portable equipment; Traffic actuated controllers; Traffic congestion; Traffic control; Traffic delays
• Old TRIS Terms: Freeway entrances and exits; Freeway ramps; Metering; Traffic control systems
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00224882
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS
• Created Date: Aug 12 1994 12:00AM