Analysis and methods of improvement of safety at high-speed rural intersections.

Details

• Alternative Title:
  Joint Transportation Research Program Technical Report Series : Civil Engineering
• Creators:
  Tarko, Andrew P. ; Leckrone, Samuel ; Anastasopoulos, Panagiotis Ch.
• Corporate Creators:
  Purdue University. School of Civil Engineering ; Purdue University. Joint Transportation Research Program
• Corporate Contributors:
  Indiana Department of Transportation ; United States. Federal Highway Administration
• Subject/TRT Terms:
  • Rural areas
  • Rural highways
  • Rural transportation
  • Intersections
  • Traffic models
  • Traffic speed
  • Traffic safety
  • Countermeasures
  • Safety
  • Multivariate analysis
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• Publication/ Report Number:
  FHWA/IN/JTRP-2012/01
• Resource Type:
  Tech Report
• Geographical Coverage:
  Indiana
• Edition:
  Final report.
• Corporate Publisher:
  Purdue University. Joint Transportation Research Program
• Abstract:
  Since 2006, INDOT has been preparing an annual five‐percent report that identifies intersections and segments on Indiana ; state roads that require attention due to the excessive number and severity of crashes. Many of the identified intersections are two‐way, stopcontrolled ; intersections located on high‐speed, multi‐lane, rural roads. Some contributing design and human factors have been identified while ; other factors still await investigation. Multivariate ordered probit models have been developed to help identify additional factors of the ; frequency and severity of crashes. These models can estimate how much different factors increase the frequency of crashes at several levels of ; injury severity (fatal/incapacitating, non‐incapacitating/ possible, property‐damage‐only). They have a unique ability to account for unobserved ; but common conditions that affect all of the crash severity levels. Recommendations for safety countermeasures are made based on both of ; these research results and our study of published reports of other authors. ; The statistical analysis was performed on 553 existing intersections in Indiana and 72 existing intersections in Michigan using crash data reported ; during a four‐year period. The identified safety factors include: presence of horizontal curves within the intersection vicinity, traffic volume on ; the major road, land use, population of the area surrounding the intersection, and the minor road functional class (traffic volume on minor road ; unknown), nearby at‐grade railroad crossings, intersection conspicuity to drivers on the major road, acceleration lanes for both left and right ; turns, median width, intersection angle, and number of intersection legs. These results are in line with other research results as documented in ; the literature review. Based on the results of this and other studies, recommendations are made to improve safety at new intersections as well as ; at existing intersections. For new intersections, construction of medians wider than 80 feet is suggested. Where this is not possible and a ; narrower median needs to be constructed, adding a parallel acceleration lane for vehicles turning left from the minor road is suggested. ; Intersections should be placed at a sufficient distance from horizontal curves and from at‐grade railroad crossings. Solutions with indirect leftturn ; lanes (Michigan U‐turns, J‐turns) are recommended. At existing intersections experiencing excessive numbers of crashes involving vehicles ; from the minor road, median closure should be considered or a median opening should be restricted to certain maneuvers. Median acceleration ; lanes can be added in order to allow a two‐stage maneuver for left turns from the minor road. Enhanced guide and warning signage can be used ; to improve intersection conspicuity; adding road illumination can especially help at night. The practice of adding left‐ and right‐turn bays should ; be continued as this is a proven intersection safety improvement practice. Applying these countermeasures may help improve safety and avoid ; the construction of expensive grade separations. Finally, advanced intersection collision avoidance systems, such as road‐side dynamic signs ; warning drivers on the minor road about a short gap on the major road, should be the subject of pilot studies in Indiana. Experiments in other ; states have indicated that these systems help drivers choose safe gaps.
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• Format:
  PDF
• Funding:
  SPR-3316
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/24456/dot_24456_DS1.pdf
• File Type:
  [PDF - 39.47 MB]
• Collection(s):
  US Transportation Collection
• Main Document Checksum:
  urn:sha-512:d3dcd6ccd1baeace17e2ca7915b711cdbc08477b307d5c4552a7190e5af3e69da81135fd8a70e4306e811c826ea1fde19f36726a03973855ee1284d827348e05