REEVALUATION OF TRUCK CLIMBING CHARACTERISTICS FOR USE IN GEOMETRIC DESIGN

THE EVALUATION IS SPECIFICALLY CONCERNED WITH WEIGHT HORSEPOWER RATIOS, TRUCK SPEEDS, AND GRADES AS THEY RELATE TO TRUCK OPERATING CHARACTERISTICS AND DESIGN CRITERIA FOR CLIMBING LANES. THE TRUCK GRADABILITY CURVES PRESENTED IN THE AASHO POLICY ADEQUATELY DESCRIBE THE PERFORMANCE OF TRUCKS ON HIGHWAY GRADES. THE 10TH PERCENTILE SPEED IS MORE CRITICAL AS A DESIGN CRITERION THAN THE AVERAGE SPEED. THERE IS A NEED TO CONSIDER ENTERING SPEEDS WHEN INCREASED SPEEDS DUE TO MOMENTUM GRADES PRECEDE AN UPGRADE. A MAXIMUM TOLERABLE TRUCK WEIGHT-HORSEPOWER RATIO OF 400:1 IS AN ACCEPTABLE DESIGN VEHICLE, BUT OVERLOADS ARE NOT TO BE ADDED. THE SPEED REDUCTION CRITERION FOR CLIMBING LANES AND CRITICAL LENGTHS OF GRADES OF 15MPH SHOULD BE CHANGED TO 10 MPH BECAUSE OF ACCIDENT INVOLVEMENT RATES. CONSECUTIVE CLIMBING LANES SEPARATED BY A SHORT INTERVAL OF HIGHWAY SHOULD BE CONNECTED. THE ACCELERATION PORTION OF CLIMBING LANES SHOULD BE EXTENDED TO ALLOW FOR ADEQUATE REENTRY SPEEDS. /BPR/

• Supplemental Notes:
  • Hpr, No 2-8-69-134-2
• 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

  Bureau of Public Roads /US

  400 7th Street, SW
  Washington, DC  United States  20590
• Authors:
  • Glennon, J C
  • Joyner, C A
• Publication Date: 1969-8

Subject/Index Terms

• TRT Terms: Climbing lanes; Highway design; Horsepower; Trucks; Vehicle characteristics; Vehicle performance; Weight
• Old TRIS Terms: Truck performance
• Subject Areas: Design; Highways; Motor Carriers; Safety and Human Factors;

Filing Info

• Accession Number: 00222585
• Record Type: Publication
• Source Agency: Bureau of Public Roads /US
• Files: TRIS, STATEDOT
• Created Date: Dec 22 1994 12:00AM