GUIDELINES FOR THE REMOVAL OF BRIDGE RAIL ON LOW VOLUME ROADS

In the USA there are roughly over one million kilometers of low-volume roads, generally defined as having an ADT of less than 400 vehicles per day. Several thousand kilometers have much lower traffic volumes. Several Midwestern states in the central USA were laid out on a grid system of 1 mile (1.6 km) sections and quarter sections, with a road around almost all sections and sometimes quarter sections. In Kansas there are several thousand kilometers of these low-volume roads, the majority being unpaved with gravel on earth surfaces. Widths generally range from 3 meters to 7 meters. These roads cross thousands of bridges and culverts that are narrow by today's standards. When built, intended purpose of the rails and headwalls was to keep vehicles from running off a bridge and dropping into a roadside drainage ditch. However, these old structures, built many years ago before any thought was given to "forgiving roadsides," have bridge rails and massive concrete culvert headwalls which are roadside obstacles that can contribute to serious crashes when vehicles stray from the roadway, and most are not necessary for the structural integrity of the structures. A study was conducted by Kansas State University (KSU) to analyze the crash risk to vehicles hitting these bridge rails and culvert and headwalls vs. the crash risk of the vehicle leaving the roadway assuming the rails and headwalls were removed. A survey was conducted to determine the extent of the problem in Kansas Counties and is summarized in this paper. The researchers used the computer program ROADSIDE to compare the probabilities and expected costs of crashes at bridge culvert locations with rails and culvert headwalls removed. The paper will give an overview of the computer program ROADSIDE and present details of adapting the program for the low-volume roads, bridge-rail study. It was concluded that the expected cost of these crashes was less with the rails and headwalls removed for ditch depths of 2.4 meters or greater. A detailed discussion of the analysis and results will be presented. Recommendations and conclusions for removing headrails are presented.

• Corporate Authors:

  Transportation Research Forum

  One Farragut Square South, Suite 500
  Washington, DC  United States  20006-4003
• Authors:
  • Russell Sr, Eugene R
  • Melhem, Hani G
  • Morice, Rafel E
• Conference:
  • Proceedings of the 42nd Annual Meeting of the Transportation Research Forum
  • Location: Annapolis, Maryland
  • Date: 2000-11-29 to 2000-12-1
• Publication Date: 2000

Language

• English

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 7-28

Subject/Index Terms

• TRT Terms: Bridge railings; Computer programs; Concrete culverts; Crash cushions; Ditches; Guidelines; Low volume roads; Roadside structures; Safety; Structural analysis; Traffic volume
• Geographic Terms: Kansas
• Subject Areas: Bridges and other structures; Design; Highways; Pavements; Safety and Human Factors; I22: Design of Pavements, Railways and Guideways;

Filing Info

• Accession Number: 00804769
• Record Type: Publication
• Files: TRIS
• Created Date: Jan 10 2001 12:00AM