Safety of Idaho Rural Highways under 129,000-pound Trucks

Abstract

A significant number of local highway jurisdictions in Idaho lack the engineering expertise and financial resources to conduct detailed assessments when requests are received to increase weight allowances for local roadways beyond the current legal limit for gross load weight of 80,000 pounds. Idaho Code 49-1004A (1) states “the authority having jurisdiction may designate routes … for vehicles not exceeding … 129,000 pounds, utilizing criteria established by the board based upon road and bridge structural integrity and engineering standards” These higher load limits can enable private freight organizations to better compete in domestic and global markets by allowing them to distribute freight more efficiently. The Idaho Transportation Department has the engineering staff and database resources available to evaluate road and bridge capacities on state and federal highways; however, local highway districts may not have such resources. This limits the local districts’ ability to expeditiously consider increased load requests, which in turn limits freight organizations’ ability to operate more efficiently on rural highways resulting in less competitive Idaho industries. Additionally, many local roadways are not designed or constructed to accommodate any type of heavy load. This collaborative study between the Idaho Transportation Department and the Local Highway Technical Assistance Council would provide local highway jurisdictions guidance for conducting roadway assessment from review of available data and current condition to full engineering studies where appropriate.