DESIGN OF A SAFETY WARNING SYSTEM PROTOTYPE FOR THE GULF FREEWAY

A SAFETY WARNING SYSTEM FOR URBAN FREEWAYS IS BEING DEVELOPED TO WARN MOTORISTS APPROACHING CREST TYPE VERTICAL CURVES OF STOPPAGE WAVES DOWNSTREAM OF THE CREST. SEVERAL CANDIDATE SYSTEMS WERE PROPOSED AND EVALUATED. THE RECOMMENDED DESIGN CONCEPT IS A TRAFFIC-ACTUATED SAFETY WARNING DEVICE WHICH WOULD BE LOCATED UPSTREAM OF THE OVERPASS CREST AND WHICH WOULD BE ACTIVATED WHEN CONDITIONS WARRANT. DETECTORS INSTALLED ON EACH LANE AND LOCATED STRATEGICALLY ON BOTH SIDES OF THE OVERPASS TRANSMIT TRAFFIC INFORMATION TO AN IBM 1800 DIGITAL COMPUTER LOCATED IN THE CONTROL SYSTEM. THE COMPUTER ACTIVATES AND DEACTIVATES THE WARNING DEVICE ACCORDING TO PREESTABLISHED CRITERIA. MANUAL OVERRIDE FEATURES WOULD BE BUILT INTO THE SYSTEM SO THAT ALL CONTROLS COULD BE ACCOMPLISHED MANUALLY IF DESIRED. THREE CRITICAL OVERPASS SITES WERE SELECTED FOR A PILOT INSTALLATION ON THE GULF FREEWAY. DOUBLE-LOOP DETECTORS ARE POSITIONED ON EACH LANE OF THE INBOUND FREEWAY, BOTH UPSTREAM AND DOWNSTREAM OF THE THREE OVERPASSES. EACH WARNING DEVICE IS LOCATED UPSTREAM OF THE CREST ADJACENT TO THE WINGWALL AND CONSISTS OF A 6' X 12' SIGN PANEL CONTAINING 10" BLACK LETTERS WITH THE MESSAGE CAUTION SLOW TRAFFIC WHICH FLASHING DISPLAYED ON A YELLOW NON-REFLECTORIZED PANEL. A 12" FLASHING BEACON IS ATTACHED ON THE RIGHT AND LEFT SIDES OF THE PANEL. AN ADDITIONAL 12" FLASHING BEACON IS MOUNTED AT THE CREST ON A POST ADJACENT TO THE RIGHT SIDE GUARDRAIL. /FHWA/

• Supplemental Notes:
  • RES STUDY 2-18-72-165
• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, 1600 E Lamar Boulevard
  Arlington, TX  United States  76011

  Texas State Department of Highways & Public Transp

  11th and Brazos Streets
  Austin, TX  United States  78701
• Authors:
  • Dudek, C L
  • Biggs, R G
• Publication Date: 1972-5

Media Info

• Pagination: 36 p.

Subject/Index Terms

• TRT Terms: Curves (Geometry); Freeways; Stopping; Traffic actuated controllers; Traffic control devices; Traffic signs; Urban highways; Warning systems
• Uncontrolled Terms: Stopped vehicles; Vertical curvature
• Old TRIS Terms: Freeway signs
• Subject Areas: Highways; Operations and Traffic Management;

Filing Info

• Accession Number: 00225025
• Record Type: Publication
• Source Agency: Federal Highway Administration
• Report/Paper Numbers: No 165-4
• Files: TRIS, USDOT, STATEDOT
• Created Date: Apr 30 1973 12:00AM