Reasonable Speed Limits on Suburban Multilane Highways with Curbs

When some two-lane roads with 55 mph speed limits are widened to four through lanes, curb and gutter is installed to address issues such as access control, difficult terrain, and limited right-of-way. Posted speed limits along such highway segments are typically decreased to 45 mph in North Carolina because of guidance in the AASHTO Green Book and elsewhere that vertical curbs should not be placed next to high-speed lanes. Although much money is spent to improve such roadways, the results may be viewed negatively by the public, design professionals, and law enforcement personnel. Drivers may be unhappy about getting tickets or driving more slowly, designers are unhappy about being blamed by the public, and police are unhappy about the increased enforcement burden. To help resolve such a dilemma, in this research the team collected relevant data such as speeds and collisions on four-lane road sections with curbs that have 45 or 55 mph speed limits and nontraversable medians or two-way left-turn lanes. The team found that the speed limit does not seem to make an important difference in collision rates or severities for the roads the team examined. The higher speed limit also made relatively small differences in the mean speeds and speed variances observed. Considering all results, the researchers recommended that the North Carolina Department of Transportation continue its current policy of allowing 55 mph speed limits on four-lane roads with curbs on a selective, case-by-case basis.

• Record URL:
  • https://doi.org/10.3141/1969-04
• 
• Summary URL:
  • http://scholar.google.com/scholar_lookup?title=Reasonable+Speed+Limits+on+Suburban+Multilane+Highways+with+Curbs&author=J.+Baek&author=J.+Hummer&author=B.+Williams&author=C.+Cunningham&publication_year=2006
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/isbn/0309099781
• Authors:
  • Baek, Jongdae
  • Hummer, Joseph E
  • Williams, Billy M
  • Cunningham, Christopher M
• Publication Date: 2006

Language

• English

Media Info

• Media Type: Print
• Features: Figures; References; Tables;
• Pagination: pp 10-17
• Monograph Title: Highway Safety: Law Enforcement; Alcohol; Driver Training; Safety Planning and Management; Commercial Vehicles; and Motorcycles
• Serial:
  • Transportation Research Record: Journal of the Transportation Research Board
  • Issue Number: 1969
  • Publisher: Transportation Research Board
  • ISSN: 0361-1981

Subject/Index Terms

• TRT Terms: Crash rates; Crash severity; Curbs; Four lane highways; Gutters; Speed limits; Two lane highways
• Identifier Terms: North Carolina Department of Transportation
• Uncontrolled Terms: Highway widening
• Subject Areas: Design; Highways; Safety and Human Factors; I20: Design and Planning of Transport Infrastructure; I80: Accident Studies;

Filing Info

• Accession Number: 01031627
• Record Type: Publication
• ISBN: 0309099781
• Files: TRIS, TRB, ATRI
• Created Date: Aug 24 2006 7:42AM