SQUIRREL HILL TUNNEL OPERATIONS STUDY

A TRAFFIC OPERATIONS STUDY WAS CONDUCTED ON THE WEST BOUND PENN LINCOLN PARKWAY IN THE VICINITY OF SQUIRREL HILL TUNNEL IN PITTSBURGH TO DETERMINE MEANS OF IMPROVING AND MAINTAINING OPTIMUM TRAFFIC OPERATIONS DURING THE CONGESTED MORNING PEAK PERIOD. PHOTOGRAPHIC TECHNIQUES WERE EMPLOYED WHICH PERMITTED THE SIMULTANEOUS OBSERVATION AND MEASUREMENT OF TRAFFIC CHARACTERISTICS AT LOCATIONS UPSTREAM, DOWNSTREAM, AND AT CRITICAL CONTROLLING POINTS FOR INTERVALS OF TIME BEFORE, DURING AND AFTER CONGESTION. THE STUDY RESULTS INCLUDE TIME AND DISTANCE PROFILES OF SPEED, VOLUME, AND DENSITY CHARACTERISTICS AND THE INTERRELATIONSHIPS AMONG THESE CHARACTERISTICS. THE COMPARISON OF TRAFFIC CHARACTERISTICS BETWEEN LANES AND THE ESTIMATION OF TRAFFIC DEMAND WERE PERMITTED BY THE ANALYSIS. RESULTS ARE RECORDED OF AN INVESTIGATION TO DETERMINE THE EFFECT OF TRUCKS ON TIME HEADWAYS AND TRAVEL TIME STUDIES. THE RESULTS OF THE SPEED-VOLUME-DENSITY PROFILES, SPEED-VOLUME-DENSITY RELATIONSHIPS, AND THE TRAVEL SPEED CONTOUR MAPS CLEARLY INDICATE THAT THE CRITICAL LOCATION ON THE STUDY SECTION IS AT THE SQUIRREL HILL TUNNEL. CONGESTION ORIGINATES NEAR THE TUNNEL ENTRANCE AND RESTRICTS THE CAPACITY OF THE STUDY SECTION. THE VARIOUS SOLUTIONS OFFERED BY THIS STUDY TO RELIEVE CONGESTION WERE CONSIDERED ON THE BASIS OF THE FORECAST OF RELIEF TO BE EXPECTED, COST OF THE TIME NECESSARY FOR EXECUTION, AND POLITICAL CONSIDERATIONS. THE SHORT-TERM PLAN CHOSEN WAS THE LANE REVERSAL OPERATION TO PROVIDE THREE INBOUND LANES THROUGH THE SQUIRREL HILL TUNNEL DURING THE MORNING PEAK HOURS. THE TRUCK BAN, ALTHOUGH EASIEST AND LEAST EXPENSIVE, WAS REJECTED DUE TO THE LACK OF SUITABLE ROUTES THROUGH THE CITY OF PITTSBURGH. CERTAIN RAMPS WERE CLOSED DURING THE RUSH HOUR PERIOD. LONGER-RANGE PROJECTS INCLUDE THE TRAFFIC METERING PROPOSAL UNDER STUDY AND THE ULTIMATE PROVISION OF ADDED CAPACITY THROUGH ROADWAY OR TUNNEL CONSTRUCTION.

• Record URL:
  http://onlinepubs.trb.org/Onlinepubs/hrbbulletin/324/324-002.pdf
• Supplemental Notes:
  • No 324, pp 12-37, 17 FIG, 2 TAB, 13 REF Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved.
• Authors:
  • May Jr, Adolf D
  • Fielder, David G
• Conference:
  • 41st Annual Meeting of the Highway Research Board
  • Location: Washington DC, United States
  • Date: 1962-1-8 to 1962-1-12
• Publication Date: 1962

Media Info

• Media Type: Digital/other
• Monograph Title: Freeway operations
• Serial:
  • Highway Research Board Bulletin
  • Issue Number: 324
  • Publisher: Highway Research Board

Subject/Index Terms

• TRT Terms: Headways; Highway capacity; Highway operations; Operations research; Peak hour traffic; Photography; Reversible traffic lanes; Traffic; Traffic congestion; Traffic density; Traffic speed; Traffic surveys; Traffic volume; Travel time; Tunnels
• Old TRIS Terms: Metering; Traffic operations research
• Subject Areas: Bridges and other structures; Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00225234
• Record Type: Publication
• Files: TRIS, TRB
• Created Date: Aug 5 1994 12:00AM