• Identifying Bridges Critical to North Carolina Agriculture and Commerce

    NCDOT Research Project Number: 2020-20

 Executive Summary

  • Current legislation in North Carolina restricts the use of State bridge funds to Functionally Obsolete or Structurally Deficient bridges. Meanwhile, weight-restricted bridges (only allowed to transport vehicles or trucks of limited weights) do not meet the requirements for being categorized as Functionally Obsolete or Structurally Deficient. Additionally, North Carolina funding targeted for improving weight and clearance restrictions is currently limited to higher traffic volume routes. This combination of occurrences makes it possible for bridges restrictive to heavy loads to fail to qualify for State bridge improvement programs and funding targeted for improving weight and clearance restrictions. As a result, bridges that are critical nodes in North Carolina's agricultural freight network are unable to receive dedicated sources of funding for improvements or long-term viability.

    North Carolina has almost 3,000 bridges classified as weight restricted spread across the state, some of which could have significant economic value if improved. Bridges heavily traversed for agricultural and commerce purposes that do not have many convenient alternative routes that would make the bridge redundant are considered to be important bridges. However, if the bridge has a weight restriction, agricultural and commerce freight vehicles may be forced to take longer alternative routes, costing farms and businesses potential significant time costs.


                     Recommended Methodology for Scoring Weight-Restricted Bridges

    The final, ranked list of weight restricted bridges was developed through a Geographic Information System (GIS) process that expressed bridge criticality as a score derived from a comprehensive and systematic travel model to consider the frequency of demand across weight-restricted bridges (traversals) and the necessary detour to avoid the weight-restricted bridge. This process offers a system-wide, objective evaluation of weight-restricted bridges.  Based on the funding availability to improve or replace the bridges with the highest composite scores, a validation of the scores should be considered based on local input and confirmation of the importance of the bridge for local, impacted businesses. 

Daniel Findley
Daniel Findley; George F. List
Nick A. Pierce
Mustan Kadibhai, PE, CPM
NC State University - ITRE
NC State University

 Report Period

  • August 1, 2019 – December 15, 2020


  • Complete


  • Structures, Construction and Geotechnical

 Sub Category

  • Miscellaneous

 Related Links

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