Intersection on Horizontal Curves: Problems and Potential Solutions

Details

• Creators:
  Sun, Xiaoduan ; Sun, Ming
• Corporate Creators:
  University of Louisiana at Lafayette. Dept. of Civil Engineering
• Corporate Contributors:
  Louisiana. Department of Transportation and Development
• Subject/TRT Terms:
  Countermeasures Highway Curves Highway Safety Intersections Risk Assessment Horizontal Curves Risk Factors Safety Safety Factors SPFs
• Publication/ Report Number:
  FHWA/LA.17/630
• Resource Type:
  Tech Report
• Geographical Coverage:
  United States;Louisiana
• Edition:
  9/2018-6/2020
• Corporate Publisher:
  Louisiana. Department of Transportation and Development
• Abstract:
  Horizontal curves and intersections pose challenges to drivers and other roadway users because of their unique design and function, which is why both features have been recognized as the target areas for safety improvement in many states’ highway safety strategies. There is little research on assessing safety of intersections on horizontal curves. Thus, this project’s goal was to quantitatively investigate safety of intersections on curves, specifically the Two-Way Stop-Controlled (TWSC) intersections. The analysis results show that clearly there is a safety problem associated with intersections placed on horizontal curves and the magnitude of the problem depends on the AADT, curve radius, intersection skewness angle, number of intersection legs and speed limit on major road. The single- vehicle crashes are the most common type of crashes on curve intersections, particularly on rural two-lane highway. Using the risk analysis process developed to facilitate the systemic safety approach, the project develops the ranking models for TWSC intersection on curves. With the rich data created by this project, the safety performance models for TWSC intersections on rural and urban two-lane highways are developed, which includes AADT, curve radius, and intersection skewness as independent variables. Based on the analysis and final site investigation, the research strongly recommends using the following low-cost speed reduction strategies to reduce roadway departure crashes at TWSC curved intersections with small curve radius even though these intersections have not manifested high yearly single vehicle crashes due to their light traffic volume: adding exclusive left-turn lane on major roadways with high AADT and left-turning traffic volume; making stop bar visible, moving stop bar forward, and trimming bushes regularly in summertime for better sight-distance on minor roads; and installing intersection on curve signs that are currently not widely used in the state.
• Format:
  PDF
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:07ea972d12e8764c7b1441c9d43f2f9594d3f181496f5ecdad89ee6e80da4188a4a2d695f92fbb55ed6722a66bd17832aeee032a8afaa8ce523e788148c519bd
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/58354/dot_58354_DS1.pdf
• File Type:
  [PDF - 2.67 MB ]