FREEWAY DESIGN ELEMENTS ON GRADES: A USER'S MANUAL

Traffic flow on grades is strongly influenced by the length and steepness of the grade, and the percentage and performance capabilities of trucks in the traffic mix. This manual provides charts and procedures for the calculation of operating speeds and service levels in mixed flows of trucks and passenger cars on grades of multilane facilities, based on recent research findings. Special attention is given to the situation where a third lane is added and then dropped to maintain service on an extended upgrade. In addition, design procedures are provided for short upgrades and for down-grades where trucks may crawl to maintain speed control. The possibility of short periods of depressed service during hours of otherwise acceptable service is also addressed, with quantitative procedures given. /Author/

• Supplemental Notes:
  • Sponsored by Federal Highway Administration, Implementation Division
• Corporate Authors:

  Midwest Research Institute

  425 Volker Boulevard
  Kansas City, MO  United States  64110-2299
• Authors:
  • St John, A D
  • Glauz, W D
• Publication Date: 1977-8

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 97 p.

Subject/Index Terms

• TRT Terms: Freeways; Highway design; Level of service; Manuals; Mathematical models; Motor vehicles; Slopes; Speed; Traffic flow; Traffic lanes; Traffic speed; Trucks
• Uncontrolled Terms: Grades
• Old TRIS Terms: Freeway design
• Subject Areas: Design; Highways; Motor Carriers;

Filing Info

• Accession Number: 00174427
• Record Type: Publication
• Source Agency: National Technical Information Service
• Report/Paper Numbers: FHWA-IP-77-18 Final Rpt.
• Contract Numbers: 42-21-6120
• Files: TRIS
• Created Date: Jun 14 1978 12:00AM