The State of the System Report is a compilation of the physical inventory and status of the Maricopa County Department of Transportation’s infrastructure. It addresses roadway congestion, traffic safety, low volume road paving, bridges, and pavement conditions. Also, included are recommendations for future improvements within each of the infrastructure categories. The SOS report has been produced annually since 1998.

The 2009 Navajo Nation Long Range Transportation Plan is a twenty-year comprehensive plan developed and updated by the Navajo Division of Transportation in a five-year cycle. The plan identifies the Nation’s multi-modal transportation needs over the next 20 years and develops strategies to meet them. The plan provides long range planning policies and implementation strategies for the Navajo Indian Reservation Roads Program improvements. It is based on a comprehensive analysis of all pertinent factors and issues affecting the Navajo Nation’s existing and future transportation needs.

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.