CURRENT COLLECTOR-DISTRIBUTOR ROAD DESIGN PRACTICES

The reconstruction of major urban freeways frequently includes the provision of collector-distributor (C-D) roads. In this paper, design issues are evaluated for C-D roads and slipramps along a 16-mi portion of I-270, located between Washington, D.C., and Frederick, Maryland. Design-year traffic volumes along I-270 are estimated to exceed 8,000 vehicles per hour in the peak direction. A literature review indicated that only minimal information was available concerning slipramp and C-D road geometric design. Operational data obtained from Texas and Illinois were referenced in the development of the geometric design for I-270. The recommended C-D road design consists of 12-ft-wide lanes for two-lane and three-lane C-D roads; a 15-ft-wide lane was recommended for one-lane C-D roads. Minimum desirable shoulder widths were determined to be 4 ft left and 14 ft right, with an absolute minimum of 4 ft. The recommended separation between the mainline and C-D road was 18 ft. The recommended slipramp design consists of a 15-ft-wide lane with 4-ft-wide left and right shoulders and adequate acceleration and deceleration lane lengths. In order to prohibit improper wrong-way use of the slipramp, the separation between the mainline and C-D road was bowed out to 42 ft to accommodate overlapping traffic barriers.

• Record URL:
  • http://onlinepubs.trb.org/Onlinepubs/trr/1987/1122/1122-003.pdf
• Record URL:
  • https://scholar.google.com/scholar_lookup?title=CURRENT+COLLECTOR-DISTRIBUTOR+ROAD+DESIGN+PRACTICES&author=P.+Stefaniak&author=D.+Wallace&publication_year=1987
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/030904474x
• Supplemental Notes:
  • Publication of this paper sponsored by Committee on Geometric Design. Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the Transportation Research Board of the National Academy of Sciences. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Copyright © National Academy of Sciences. All rights reserved
• Authors:
  • Stefaniak, Peter R
  • Wallace, David W
• Publication Date: 1987

Media Info

• Media Type: Print
• Features: Figures; Maps; References; Tables;
• Pagination: pp 18-26
• Monograph Title: Geometric design and operational effects
• Serial:
  • Transportation Research Record
  • Issue Number: 1122
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Acceleration lanes; Deceleration lanes; Design volume; Distance; Geometric design; Highway design; Length; Peak hour traffic; Prevention; Road shoulders; Streets; Traffic lanes; Traffic volume; Width; Wrong way driving
• Uncontrolled Terms: Separation
• Old TRIS Terms: Collector distributor roads; Slipramps; Traffic lane width
• Subject Areas: Design; Highways; Planning and Forecasting; Security and Emergencies; I21: Planning of Transport Infrastructure;

Filing Info

• Accession Number: 00468652
• Record Type: Publication
• ISBN: 030904474x
• Files: TRIS, TRB, ATRI
• Created Date: May 31 1988 12:00AM