This study investigated whether highways acted as barriers to gene flow for pronghorn in northern Arizona. DNA samples from 132 pronghorn were analyzed using eight polymorphic microsatellite loci. Samples represented animals living on opposite sides of US Route 89 (US 89) and State Route 64 (SR 64). Two different modeling approaches indicated that both US 89 and SR 64, and to a lesser extent US Route 180 (US 180), acted as barriers to gene flow. The genetic structuring caused by highways, especially across US 89, is consistent with behavioral data that demonstrated pronghorn rarely cross this highway. This study found no evidence of inbreeding or reduced genetic variation in any of the populations examined, but those effects may take longer to appear. Based on these results, the researchers recommend future genetic monitoring of these populations or assessment of genetic variation across highways with larger traffic volumes or longer histories to determine whether the barrier effects documented here lead to loss of genetic diversity.

The Arizona transportation history project was conceived in anticipation of Arizona’s centennial, which will be celebrated in 2012. Following approval of the Arizona Centennial Plan in 2007, the Arizona Department of Transportation recognized that the centennial celebration would present an opportunity to inform Arizonans of the crucial role that transportation has played in the growth and development of the state.

The report consists of a historical narrative and a series of topical essays. The seven-chapter historical narrative is a history of Arizona’s highways that extends from the pre-Columbian era to the present. The 14 topical essays extend the scope of the history beyond the state’s highway system. They include overviews of the development of other transportation modes (railroads, aviation, and urban transit), a brief history of highway pavements, a lighthearted look at the motoring experience during the 1920s and 1930s, and an exploration of how changes in transportation infrastructure affected some Arizona communities. The topical essays also provide additional historical information on bridges, urban freeways, the Interstate system, ADOT and its predecessor agencies, and famous roads such as U.S. Route 66, U.S. Route 89, the Black Canyon Highway, and the Beeline Highway.

The report also includes a timeline of transportation-related developments. This chronology not only provides an accessible overview of Arizona’s transportation history; it also places that history in a larger context by including transportation-related developments from the rest of the nation and around the world. Finally, the report contains a guide to archives in Arizona that hold significant collections of historical photographs related to the state’s transportation history, a bibliography of published historical sources related to the history of highways in Arizona, and a discussion of how the historical narrative and topical essays could be used to produce publications and media that would be made available to the public.

The Arizona Department of Transportation (ADOT) operates a transportation library. The mission of the ADOT Library is to provide ADOT employees with the published information they need to carry out their job responsibilities contributing to a safe, efficient, and cost-effective transportation system in Arizona. Historically, ADOT's librarians have used professional judgment to decide which materials to add to the collection. This research is the first formal investigation to determine the information needs of ADOT staff and the role of the Library in meeting those needs. This study has provided information regarding: (a) the information needs of the ADOT staff, including the means by which they currently obtain the information they need; (b) preferences regarding access to Library services and resources; and (c) awareness and use of the ADOT Library. Findings from the study also provided insights into the role of transportation libraries, the extent to which ADOT Library practices align with acknowledged effective practices in transportation libraries overall, and opportunities for ongoing improvement and enhancement of Library operations, communications and marketing efforts, customer service, and valuation. Recommendations were developed to facilitate delivery of ADOT Library services in fiscal periods characterized by severe budgetary constraints and limited resources as well as in less constricted fiscal periods permitting continued investment in ADOT Library resources (staff, collection materials, information technologies). The research findings can be used by ADOT to inform strategic and contingency planning efforts and will enable ADOT to make data-driven decisions regarding the Library collection and services.