California Department of Transportation

Research Reports and Summaries


Preliminary Investigations are literature reviews that provide a comprehensive overview of historical and existing national and international research and best practices for defined research needs.


Research Notes provide an overview of research in progress to a general audience. Released at the beginning of a research task, the notes describe the research need, methodology, goal, benefits, milestones, and next steps.


Final Reports document the executed methodology, detailed findings, and technical analysis for completed research tasks.


Research Results are two-page briefs written for the general audience to quickly and concisely communicate the results of completed research tasks. Research Results complement the final report by highlighting the research need, goal, methodology, outcome, and benefit.


The Annual Report highlights the research program's yearly achievements, activities, and research results.


The Research Manual provides in-house researchers, Caltrans staff, academic and private-sector researchers, and others interested in DRI’s program with the information they need to develop, select, fund, and implement research that benefits the traveling public in California.