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    <copyright>Copyright © 2026. National Academy of Sciences. All rights reserved.</copyright>
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    <managingEditor>tris-trb@nas.edu (Bill McLeod)</managingEditor>
    <webMaster>tris-trb@nas.edu (Bill McLeod)</webMaster>
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      <title>PREDICTIVE ANALYSES OF THE PERFORMANCE OF A HEADWAY CONTROL SYSTEM FOR HEAVY COMMERCIAL VEHICLES. CONFERENCE PAPER</title>
      <link>https://trid.trb.org/View/411873</link>
      <description><![CDATA[This paper presents the results of analyses aimed at examining the performance of a vehicle system consisting of a heavy truck, range and range-rate sensors for measuring the relative motion of a leading vehicle, a cruise control modified to accept velocity commands, and a control unit for switching in and out of a headway-control mode.  A control strategy, that approximately transforms the system into an equivalent first order system, is described.  Physical interpretations of the meanings of the control system parameters are made using simulation results to illustrate the influences of design choices and measurement errors.]]></description>
      <pubDate>Thu, 09 Feb 1995 00:00:00 GMT</pubDate>
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      <title>EVOLUTION OF AIRTRANS -- A SUCCESSFUL AGT SYSTEM</title>
      <link>https://trid.trb.org/View/146425</link>
      <description><![CDATA[The AIRTRANS automated guideway transit (AGT) in operation at Dallas/Fort Worth (D/FW) Airport is the largest and most sophisticated AGT system in revenue service today.  The system covers 12.83 miles of guideway, 14 passenger and 14 employee stations and 33 interlocking diverge switches. There are five passenger and four employee routes.  There are a total of 51 passenger vehicles (31 lead and 20 trail) which are operated in one and two vehicle consists to provide an average of 25 trains (allowing 6 spares) in service at any one time.  The vehicles are controlled by a conventional "fixed block" headway control system which is monitored and supervised by a distributed computer surveillance system.  To date the system has accumulated over 16 million vehicle miles and 22 million passenger trips with a system availability above 99%.  In the 1974-1976 time period several independent assessments indicated improvements which would be required to successfully deploy AIRTRANS in an urban environment.  Utilizing these data, a program designated "AIRTRANS Urban Technology Program" was defined and initiated by UMTA in December 1976.  This program, conducted in two phases, will result in the demonstration of an improved, higher performance, urban deployable vehicle at D/FW Airport in October 1979.]]></description>
      <pubDate>Tue, 15 Jan 1980 00:00:00 GMT</pubDate>
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      <title>CONTROL CONSIDERATIONS FOR SHORT-HEADWAY ACGV SYSTEMS</title>
      <link>https://trid.trb.org/View/7386</link>
      <description><![CDATA[Command and control systems for automatically controlled and guided vehicle (ACGV) systems were investigated with emphasis on systems for short (up to 30 seconds) headway operation.  Ten proposed systems which employ either conventional block control techniques or one or more large digital processors were evaluated.  The conventional block approach and the central computer approach were both used in the study.  (Author)]]></description>
      <pubDate>Fri, 09 Mar 1973 00:00:00 GMT</pubDate>
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      <title>INTRA-AIRPORT TRANSPORTATION SYSTEMS: AN EXAMINATION OF TECHNOLOGY AND EVALUATION METHODOLOGY</title>
      <link>https://trid.trb.org/View/132152</link>
      <description><![CDATA[THE PROBLEMS ASSOCIATED WITH THE MOVEMENT OF PEOPLE AND BAGGAGE WITHIN AN AIRPORT ARE ONES OF CONGESTION, LONG WAITING TIMES, AND LONG WALKING DISTANCES. THESE RESULT FROM AN INCREASINGLY HEAVY, BUT UNEVENLY DISTRIBUTED, DEMAND FOR AIR TRAVEL, AND INADEQUATE AND SPRAWLING FACILITIES. THERE IS GENERAL AGREEMENT AMONG AUTHORITIES IN THE FIELD OF COMMERCIAL AVIATION THAT UNLESS NEW AND IMAGINATIVE SOLUTIONS TO THE PROBLEM ARE FOUND, THE SITUATION WILL GET WORSE. AUTOMATED TRANSPORTATION SYSTEMS CAN BE GROUPED INTO THREE CATEGORIES ACCORDING TO THE COMPLEXITY OF THE CONTROL SYSTEM. IN CATEGORY 1, ARE SYSTEMS WITH HEADWAYS OF SEVERAL TIMES THE MINIMUM SAFE STOPPING DISTANCE. AUTOMATIC SWITCHES FOR THESE SYSTEMS MAY BE LOCATED IN THE GUIDEWAY AND REQUIRE SEVERAL SECONDS FOR ONE SWITCHING OPERATION. THE TRANSPORTATION DEMANDS OF MOST AIRPORTS CAN BE MET BY CATEGORY 1 AUTOMATED TRANSPORTATION SYSTEMS WITH CARS OF MEDIUM CAPACITY (20 PASSENGERS) OPERATING IN TRAINS. BECAUSE THE GUIDANCE AND CONTROL TECHNOLOGY IS AVAILABLE NOW AND HAS BEEN DEMONSTRATED FOR THE BART SYSTEM, THE ONLY MAJOR NEW TECHNOLOGICAL IMPROVEMENT REQUIRED IS THE DEVELOPMENT OF AN AUTOMATED SWITCH. IN CATEGORY 2, ARE SYSTEMS WHICH HAVE HEADWAYS OF SLIGHTLY GREATER THAN ONE SAFE STOPPING DISTANCE; AND WHICH REQUIRE A FAST-ACTING SWITCH LOCATED ON-BOARD THE VEHICLE. FOR ALL PRACTICAL PURPOSES, THE FREQUENTLY PROPOSED SMALL CAR (APPROXIMATELY SIX PASSENGERS), DEMAND-ACTIVATED SYSTEMS MUST OPERATE AS DO CATEGORY 2 SYSTEMS TO MEET AIRPORT REQUIREMENTS. EVEN THEN, THEY ARE ABLE TO MEET ONLY THE INTRATERMINAL MOVEMENT REQUIREMENT, ALTHOUGH IT IS APPARENT THAT THE OPTION OF OPERATING IN SINGLE UNITS OR IN MULTIPLE CAR TRAINS WOULD GREATLY EXPAND THEIR CAPACITY RANGE. ALTHOUGH CATEGORY 3 SYSTEMS HAVE BEEN PROPOSED FOR AIRPORT APPLICATIONS, THE TECHNOLOGICAL AND SAFETY PROBLEMS ASSOCIATED WITH THEM INDICATE THAT INTRODUCTION OF SUCH ADVANCED FORMS OF TRANSPORTATION IS YEARS AWAY. /UMTA/]]></description>
      <pubDate>Tue, 07 Nov 1972 00:00:00 GMT</pubDate>
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