In 1993, the Arizona-Mexico Commission and its sister organization, the Comisión Sonora-Arizona, initiated a binational strategic economic planning process to analyze how the two neighboring states could increase their regional competitiveness in the world economy and enhance the overall quality of life for their residents. One of the recommendations of the Strategic Economic Development Vision was to develop a set of indicators as a tool to monitor progress toward the goals of binational economic development. The purpose of the Regional Economic Indicators is to help policy and decision-makers understand and monitor economic changes in the Arizona-Sonora region and to support policies that promote economic transformation, investment and entrepreneurship in the region.

The study reported here was designed to examine the impact of background meteorological conditions on the propagation of noise from urban freeways in the Phoenix area. The aim was to understand and predict how sound waves emanating from highways respond to the vertical profiles of atmospheric temperature gradients and velocity shear, so that sound measurements can be interpreted with regard to the environmental variability.