Highway traffic noise barriers in the U.S. - Construction trends and cost analysis

For a number of years, the U.S. Department of Transportation (DOT) and the Federal Highway Administration (FHWA) have been compiling data on highway traffic noise barriers constructed in the U.S. in an effort to identify trends and to measure and document progress of the States in addressing the issue of highway traffic noise impact on communities. As part of this effort, FHWA’s Office of Natural Environment issues a call on a triennial basis to all the fifty States, the District of Columbia, and the Commonwealth of Puerto Rico for updates and summaries of local/state-level noise barrier construction activity that has occurred in the last three-year period. FHWA then compiles and analyzes the data into a running list of noise barriers for each State/jurisdiction and publishes two documents. The first report summarizes the individual project or barrier related costs and other physical characteristics for all noise barriers constructed by each State/jurisdiction to date. As part of the overall document, the actual listing of all barriers as reported by each State is also included. The second document provides some statistical analysis of the data to identify general national trends pertaining to highway traffic noise barrier construction. One key factor to note in the FHWA data compilation is that the data are reported based upon each State’s own criteria, practices, and procedures. There is no universally applied method or guidance for reporting cost and other barrier data from State to State. In the determination of costs associated with noise barriers, every State has its own criteria and factors for determining what is included in the reported cost of a noise barrier. For example, one State may use the overall bid cost for a project, while another may quote only the cost of the barrier material or “system” (i.e., posts, panels and foundations), while yet another State may include a combination of various cost elements. The methods for reporting data on the physical dimensions of the barriers are subject to somewhat less State-to- State variation; however, the overall accuracy of all the data is not fully verifiable. In addition, because some of the State running lists of barrier information may span a period of 20 years or more, there is a good chance that the individual State’s methods or criteria for reporting costs and other data have not remained static or consistent over time. Therefore, in the absence of uniform guidance on reporting information on noise barrier construction, care must be exercised in all comparisons.