EVALUATION OF DIAGRAMMATIC SIGNING

A RESEARCH PROJECT WAS UNDERTAKEN TO EVALUATE THE EFFECTIVENESS OF DIAGRAMMATIC HIGHWAY SIGNS IN REDUCING ERRATIC BEHAVIOR BY DRIVERS. BEFORE-AND-AFTER VISUAL OBSERVATIONS AND DRIVER INTERVIEWS WERE CONDUCTED AT TWO STUDY AREAS IN THE CHEYENNE (WYO.) AREA: A TRUMPET-TYPE INTERCHANGE JUST NORTH OF THE INTERCHANGE BETWEEN I-25 AND I-80, AND A DIRECTIONAL INTERCHANGE WEST OF THE CITY THAT IS THE FIRST INTERCHANGE SIGNED FOR THE BUSINESS LOOP. VEHICLE MOVEMENTS WERE DIVIDED INTO TWO GROUPS: (1) STOPS OR NEAR STOPS TO READ THE SIGNS, ABRUPT OR LAST-MINUTE TURNS, AND DEFINITE HESITATIONS; AND (2) ACTUAL WRONG TURNS RESULTING IN BACKING, CIRCLING THE INTERCHANGE, OR RETURNING BY A DIFFERENT ROUTE. MEANS OF MAINTAINING EQUIVALENT CONDITIONS FOR THE BEFORE AND AFTER SEGMENTS OF THE PROJECT ARE DESCRIBED. IT WAS FOUND THAT THE DIAGRAMMATIC SIGNS DID NOT SUBSTANTIALLY REDUCE ERRATIC MOVEMENTS; HOWEVER, INTERVIEWS ESTABLISHED THAT "BEFORE" THE CONFUSION AROSE FROM THE SIGNS THEMSELVES, WHILE "AFTER" IT STEMMED FROM DRIVERS' INDECISION AS TO WHICH ROUTE TO CHOOSE. ON THIS GROUND IT IS SUGGESTED THAT FURTHER EXPERIMENTS BE UNDERTAKEN, POSSIBLY USING DIAGRAMMATIC SIGNS IN LIEU OF EXISTING MAINLINE INTERSTATE SIGNS RATHER THAN AS A SUPPLEMENT TO THEM AS WAS THE CASE HERE.

• Supplemental Notes:
  • 22 Pp, 8 FiG, 6 TAB
• Corporate Authors:

  Wyoming State Highway Department

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• Publication Date: 0

Subject/Index Terms

• TRT Terms: Before and after studies; Behavior; Diagrams; Drivers; Interstate highways; Signs; Traffic signs
• Identifier Terms: Interstate Highway System
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00226038
• Record Type: Publication
• Files: TRIS, STATEDOT
• Created Date: Sep 6 1971 12:00AM