ANATOMY OF A JACKKNIFE

THE BASIC CAUSE OF ANY JACKKNIFE IS A TWISTING MOMENT SET UP WITHIN THE SYSTEM BY UNBALANCED PROPELLING AND RESISTING FORCES. WHENEVER THE TWISTING MOMENT EXCEEDS THE RESISTING MOMENT AS DEVELOPED BY THE TIRES ON THE ROAD SURFACE, A JACKKNIFE IS PROBABLE, JACKKNIVES ARE CAUSED BY SKIDDING. SIX BASIC TYPES OF SKIDS ARE FRONT WHEEL, REAR WHEEL, ALL WHEEL, SPINOUT, POWER SKIDS, AND HYDROPLANING. AS A RULE OF THUMB MEASUREMENT, HYDROPLANING WILL OCCUR AT NINE TIMES THE SQUARE ROOT OF THE TIRE PRESSURE. SOME FACTORS INVOLVED IN JACKKNIFING ARE: DRIVER, VEHICLE, MAINTENANCE, BRAKE SYSTEM. LOAD, TIRE CONDITION, ROAD SURFACE, WEATHER, AND PANIC STOP SITUATION. MAJOR POINTS OF THE BOOKLET "KEEP ROLLING WITH SAFETY IN WINTER WEATHER" PUBLISHED BY THE NATIONAL SAFETY COUNCIL ARE GIVEN. PRECAUTIONS TO TAKE TO AVOID JACKKNIVES ARE DISCUSSED. THIS PERTAINED TO DRIVER EDUCATION, TIRE TREAD AND PRESSURE, BRAKES, ROAD SURFACES AND FRICTION COEFFICIENT. THE NATIONAL HIGHWAY SAFETY BUREAU IS CURRENTLY PROPOSING REGULATIONS REQUIRING MORE STRINGENT BRAKE PERFORMANCE CAPABILITIES ALONG WITH "ANTI-LOCKUP" SYSTEMS TO BE INSTALLED ON BOTH TRACTORS AND TRAILERS. NEXT TO A FRONT TIRE BLOWOUT, THE TYPICAL ROAD DRIVER FEARS THE JACKKNIFE MOST.

• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/oclc/23150828
• Supplemental Notes:
  • Vol 66, No 1, PP 61-66, 1 FIG, 2 PHOT
• Authors:
  • BALD, J
• Publication Date: 1971-1

Media Info

• Serial:
  • Fleet Owner
  • Publisher: Primedia Business Magazines & Media, Incorporated
  • ISSN: 1070-194X
  • Serial URL: http://www.fleetowner.com

Subject/Index Terms

• TRT Terms: Brakes; Canal lock operations; Driver training; Engineering moments; Highway safety; Hydroplaning; Jackknifing; Pavements; Skid resistance; Skidding; Surface course (Pavements); Tires; Trailers; Truck tractors; Vehicle maintenance; Weather; Wheels
• Old TRIS Terms: Moments
• Subject Areas: Highways; Maintenance and Preservation; Pavements; Safety and Human Factors; Vehicles and Equipment;

Filing Info

• Accession Number: 00223417
• Record Type: Publication
• Files: TRIS
• Created Date: Apr 10 1971 12:00AM