Guidelines for spacing between freeway ramps.

Details

• Creators:
  Fitzpatrick, Kay ; Porter, Richard J. ; Pesti, Geza ; Chu, Chi-Leung ; Park, Eun Sug ; Le, Thanh
• Corporate Creators:
  Texas Transportation Institute
• Corporate Contributors:
  Texas. Dept. of Transportation. Research and Technology Implementation Office ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Freeway operations
  • Ramps (Interchanges)
  • Weaving sections Express highways--Texas--Design and construction
  • Roads--Texas--Interchanges and intersections--Design and construction.
• Publication/ Report Number:
  FHWA/TX-10/0-5860-1
• Resource Type:
  Tech Report
• Geographical Coverage:
  Texas
• Edition:
  Technical Report; Sept. 2007¿Aug. 2009.
• Corporate Publisher:
  Texas Transportation Institute
• Abstract:
  Existing geometric design guidance related to interchange ramp spacing in the Texas Roadway Design ; Manual and the AASHTO’s A Policy on Geometric Design of Highways and Streets (Green Book) is not ; speed-dependent even though intuition indicates spacing and speed are related. Understanding the ; relationship between interchange ramp spacing, speed, and freeway operations is important, especially in ; developing potential design values for higher speeds (e.g., 85 to 100 mph). The objectives of this project ; were to: (a) investigate relationships between weaving length, speed, and overall vehicle operations on ; Texas freeways and (b) propose updates to current Texas Department of Transportation guidance on ; recommended distances between ramps. Within the research tasks several methods were utilized to assist in ; developing guidance on ramp spacing lengths. The methods or resources used to generate potential lengths ; included: guidance provided in Design Manual for Roads and Bridges published by the Highways Agency ; in England, minimum deceleration and acceleration length for freeway conditions, decision sight distance, ; sign spacing needs, NCHRP project 3-75 findings, findings from field studies at seven study sites, findings ; from simulation conducted as part of this research, and safety relationships identified in the literature. ; Suggested ramp spacings were developed for the entrance ramp to exit ramp and exit ramp to exit ramp ; conditions.
  More +
• Format:
  PDF
• Funding:
  0-5860
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/17798/dot_17798_DS1.pdf
• File Type:
  [PDF - 1.26 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:1037cb811e1c50a4caa035cf50bbe5c3599d73b841bef92997bc8cef25b69f89c912799599143a51b10c8791acc15409bfa58421ac749ce0f6d85a5cdb1d37e2