DEVELOPMENT OF RAMP DESIGN PROCEDURES FOR FACILITIES WITHOUT FRONTAGE ROADS

Based on a recent change in Texas Department of Transportation (TxDOT) policy, frontage roads are not to be included along controlled-access highways unless a study indicates that the frontage road improves safety, improves operations, lowers overall facility costs, or provides essential access. Interchange design options that do not include frontage roads are to be considered for all new freeway construction. Ramps in non-frontage-road settings can be more challenging to design than those in frontage-road settings for several reasons. Adequate ramp length, appropriate horizontal and vertical curvature, and flaring to increase storage area at the crossroad intersection should all be used to design safe and efficient ramps for non-frontage-road settings. However, current design procedures available in standard TxDOT reference documents focus on ramp design for frontage-road settings. The objective of this research project was to develop recommended design procedures for interchange ramps on facilities without frontage roads. This report describes the findings from the second year of a two-year project. Crash data from Texas interchanges were used to calibrate several ramp safety prediction models. These models form the basis for a procedure for evaluating the safety of alternative ramp configurations. Ramp design guidelines are developed. Design controls and elements routinely considered during the ramp design process are identified. The report titled "Recommended Ramp Design Procedures for Facilities without Frontage Roads" presents this guidance in a manner suitable for application by designers.

• Record URL:
  http://tti.tamu.edu/documents/0-4538-2.pdf
• 
• Supplemental Notes:
  • Project Title: Ramp Design Considerations for Facilities without Frontage Roads.
• Corporate Authors:

  Texas Transportation Institute

  Texas A&M University System, Information Technology Exchange Center
  College Station, TX  United States  77843

  Texas Department of Transportation

  Research and Technology Implementation Office, P.O. Box 5080
  Austin, TX  United States  78763-5080

  Federal Highway Administration

  1200 New Jersey Avenue, SE
  Washington, DC  United States  20590
• Authors:
  • Bonneson, J
  • Zimmerman, K
  • Messer, C
  • Lord, D
  • Wooldridge, M
• Publication Date: 2004-9

Language

• English

Media Info

• Features: Appendices; Figures; References; Tables;
• Pagination: 92 p.

Subject/Index Terms

• TRT Terms: Crash data; Design; Design methods; Freeways; Frontage roads; Guidelines; Highway design; Highway safety; Interchanges; Length; Ramps (Interchanges)
• Uncontrolled Terms: Flared ramps; Horizontal curvature; Vertical curvature
• Subject Areas: Design; Highways; Planning and Forecasting; I21: Planning of Transport Infrastructure;

Filing Info

• Accession Number: 00989239
• Record Type: Publication
• Report/Paper Numbers: FHWA/TX-05/0-4538-2,, Technical Report 0-4538-2
• Contract Numbers: Project No. 0-4538
• Files: TRIS, USDOT, STATEDOT
• Created Date: Apr 18 2005 12:00AM