DESIGN AND CONTROL CONSIDERATIONS FOR AUTOMATED GROUND TRANSPORTATION SYSTEMS

OPERATION OF PROPOSED FUTURE METROPOLITAN GROUND TRANSPORTATION SYSTEMS, USING AUTOMATED SINGLE-LANE GUIDEWAY NETWORKS WITH CLOSELY SPACED VEHICLES, IS ANALYZED. THE IMPORTANT INDEPENDENT AND DEPENDENT SYSTEM VARIABLES AND THE ASSOCIATED CONSTRAINTS ARE IDENTIFIED, AND BASIC RELATIONSHIPS BETWEEN THESE VARIABLES ARE DISCUSSED. IN AN ATTEMPT TO FIND A USEFUL MEASURE OF PERFORMANCE, TWO HIGHLY SIGNIFICANT PERFORMANCE CRITERIA ARE FORMULATED: THE WEIGHTED AVERAGE TRAVEL TIME, AND THE RELATIVE SAFETY OF TRAVEL. BOTH ARE STRONGLY RELATED TO THE QUALITY OF SERVICE PROVIDED BY TRANSPORTATION SYSTEMS, AND CAN BE APPLIED AS USEFUL TOOLS FOR SYNTHESIZING FUTURE SYSTEMS AND EVALUATING ALTERNATIVE APPROACHES. THE MAIN CONTROL FUNCTIONS THAT ARE INSTRUMENTAL IN ACHIEVING THE DESIRED HIGH LEVEL OF PERFORMANCE IN THESE FUTURE SYSTEMS ARE IDENTIFIED AND BRIEFLY DISCUSSED. INSTEAD OF PROPOSING SPECIFIC SOLUTIONS, THE DISCUSSION ATTEMPTS TO GIVE A GOOD UNDERSTANDING OF THE CONTROL PROBLEMS OF SYSTEMS EMPLOYING A LARGE NUMBER OF AUTOMATICALLY CONTROLLED RELATIVELY SMALL VEHICLES, PARTICULARLY THOSE PROBLEMS ARISING FROM SHORT HEADWAYS AND MERGING VEHICLE FLOWS. THE HEADWAY AND MAIN LINE SPEED CONTROL ARE IDENTIFIED AS THE CONTROL FUNCTIONS MOST CRITICAL TO SYSTEM PERFORMANCE (TRAVEL TIME, CAPACITY, SAFETY). THE DISCUSSION OF THE CONTROL PHILOSOPHIES IS INTENDED AS BASIC BACKGROUND INFORMATION FOR THE SYSTEM ENGINEER UNFAMILIAR WITH THE DETAILS. IN RELATING GUIDEWAY CAPACITY TO SAFETY, THE RATIO OF MINIMUM HEADWAY TO THE NOMINAL STOPPING DISTANCE IS IDENTIFIED AS AN IMPORTANT SYSTEM PARAMETER. THE GUIDEWAY CAPACITY, THE RELATIVE SAFETY, AND THE COMPLEXITY OF THE CONTROL SYSTEM ARE EXPRESSED IN TERMS OF THIS FACTOR. THE MAIN LIMITATIONS OF THE APPROACH ARE THE COMPLEXITY OF MODERN TRANSPORTATION SYSTEMS, AND THE INHERENT DIFFICULTIES IN ASSESSING THEIR COST-BENEFIT RELATIONSHIPS. THUS, WHILE THIS PAPER IDENTIFIES THE NATURE OF MANY OF THE PROBLEMS, EXTENSIVE FURTHER RESEARCH WILL BE REQUIRED TO EXTEND THE METHOD PRESENTED HERE TO FULL-SCALE SYSTEMS. /AUTHOR/

  • Supplemental Notes:
    • Vol 56, pp 493-513
  • Authors:
    • Hajdu, L P
    • Gardiner, K W
    • Pressman, G L
    • Tamura, H
  • Publication Date: 1968-4

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  • Accession Number: 00225445
  • Record Type: Publication
  • Source Agency: Traffic Systems Reviews & Abstracts
  • Files: TRIS
  • Created Date: Apr 28 1994 12:00AM