Economic Impact of Closing Structurally Deficient or Functionally Obsolete Bridges on Very Low-Volume Roads

The state of Kansas has approximately 25,464 bridges located on state, county, and city roadway networks. As of May 2012 approximately 1,229 bridges on very low-volume roads were determined to be structurally deficient and candidate structures to be potentially closed, replaced, or repaired. This study was designed to provide such critical information for county commissioners or practicing engineers as (a) where structurally deficient or functionally obsolete bridges on low-volume roads were located, (b) what distance was the shortest drivable detour if these bridges were to be closed, and (c) whether to recommend closing or to repair or replace the structurally deficient bridges on the basis of both potential detour length and average daily traffic (ADT). The results of the study indicated that many of the structurally deficient bridges on very low-volume roadways had detours of 2 mi or less, were steel bridges, and had ADT values of fewer than eight vehicles. On the basis of the analysis, bridge closure was recommended for a low-volume roadway with an ADT value less than eight and a detour length of less than 9 mi.