ACCOMPLISHMENTS IN FREEWAY OPERATIONS IN THE UNITED STATES

ACHIEVEMENTS IN FREEWAY OPERATIONS OVER THE PAST TWO DECADES ARE NOTED UNDER FOUR MAIN HEADINGS. UNDER DESIGNS THE MAJOR ACCOMPLISHMENTS HAVE BEEN PROVIDED BY DESIGN STANDARDS AND REVERSIBLE LANES. THE SECTION ON SURVEILLANCE, COMMUNICATIONS, AND PRESENTS A CHRONOLOGICAL REVIEW OF TUNNEL TRAFFIC METERING, TELEVISION SURVEILLANCE AND ON- FREEWAY CONTROL, ELECTRONIC SURVEILLANCE AND ACCESS CONTROL, DIVERSIFICATION AND REFINEMENT OF ACCESS- CONTROL CONCEPTS, CORRIDOR ANALYSIS, FREEWAY NETWORK ANALYSIS, THE MOVING--MERGE CONTROL SYSTEM, AND COORDINATION OF FREEWAY SURVEILLANCE AND CONTROL WITH TRANSIT OPERATION. THE THIRD CATEGORY OF ACHIEVEMENT IS THE SECONDARY BENEFITS OF SURVEILLANCE AND CONTROL. THESE INCLUDE REDUCTION, DETECTION, AND REMOVAL OF PEAK-HOUR FREEWAY INCIDENTS; MOTORIST SERVICES, IMPROVED POLICE OPERATIONS, AND IMPROVED SCHEDULING OF MAINTENANCE OPERATIONS. UNDER THE FOURTH HEADING, SAFETY, ATTENTION IS FOCUSED ON FIXED- OBJECT DESIGN AND COLLISION RESEARCH.