Systematic, well-designed research provides the most effective approach to the solution of many problems facing highway administrators and engineers. Often, highway problems are of local interest and can best be studied by highway departments individually or in cooperation with their state universities and others. However, the accelerating growth of highway transportation develops increasingly complex problems of wide interest to highway authorities. These problems are best studied through a coordinated program of cooperative research. In recognition of these needs, the highway administrators of the American Association of State Highway and Transportation Officials initiated in 1962 an objective national highway research program employing modern scientific techniques. This program is supported on a continuing basis by funds from participating member states of the Association and it receives the full cooperation and support of the Federal Highway Administration, United States Department of Transportation. The Transportation Research Board of the National Academies was requested by the Association to administer the research program because of the Board's recognized objectivity and understanding of modern research practices. The Board is uniquely suited for this purpose as it maintains an extensive committee structure from which authorities on any highway transportation subject may be drawn; it possesses avenues of communications and cooperation with federal, state and local governmental agencies, universities, and industry; its relationship to the National Research Council is an insurance of objectivity; it maintains a full-time research correlation staff of specialists in highway transportation matters to bring the findings of research directly to those who are in a position to use them. The program is developed on the basis of research needs identified by chief administrators of the highway and transportation departments and by committees of AASHTO. Each year, specific areas of research needs to be included in the program are proposed to the National Research Council and the Board by the American Association of State Highway and Transportation Officials. Research projects to fulfill these needs are defined by the Board, and qualified research agencies are selected from those that have submitted proposals. Administration and surveillance of research contracts are the responsibilities of the National Research Council and the Transportation Research Board. The needs for highway research are many, and the National Cooperative Highway Research Program can make significant contributions to the solution of highway transportation problems of mutual concern to many responsible groups. The program, however, is intended to complement rather than to substitute for or duplicate other highway research programs.

High-speed signalized intersections have both safety and efficiency problems. The safety problems traditionally have been overcome by using advance detectors. However, at relatively moderate flow rates, multiple advance detector systems tend to extend the green phase to its maximum allowable duration (i.e., max-out). At max-out, drivers on the intersection approach may be faced with the decision to proceed or stop. This creates the safety problem the system was intended to prevent. Also, extending phases to their maximums increases delays to other movements. A new approach to high-speed intersection control is outlined-a dynamic dilemma zone allocation system that uses measured vehicle speeds with a control algorithm to decide when to end the signal phases. The new system was evaluated by simulation and field installation. In both instances, the new system indicated it could improve safety and maintain efficient operations at high-speed intersections.

A review of the literature suggests that errors in death certification are common. We reviewed the published literature to clarify what is known and what remains to be learned before evidence-based changes in medical education can be recommended. We searched the National Library of Medicine’s PubMed database for articles that addressed death certificate accuracy and identified 159 articles of interest published from 1996 to 2010. Among these 159 articles, we found 83 that were relevant to our goals and objectives. Cause of death certification has been shown to be problematic and several interventions have been shown to improve its accuracy, especially if the intervention is interactive. However these studies have focused on short term gains rather than on long term retention and performance, leaving a significant data gap. We suggest a study design that could address this data gap

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Decision-makers have long speculated that building separate roads for trucks and passenger cars, or at least separating them on their own lanes would accomplish two major objectives: 1) they would make the roadways safer for passenger cars, and 2) roadways designed specifically for a select class of vehicles rather than for all vehicles might represent overall savings in construction costs. This paper addressed the first objective. Recent studies on the evaluation of safety effects of truck traffic levels on general freeway facilities have not provided a clear understanding on how they affect the number of crashes. In some cases, they have been contradictory. In addition, no studies have specifically compared passenger cars-only with mixed traffic freeway facilities. The original research on which this paper is based is aimed to assess whether or not more homogeneous flows of traffic by vehicle type are safer than the current mixed flow scenario. To accomplish the objective of the study, an exploratory analysis of crash data is conducted on a selected number of freeway sections located on the New Jersey Turnpike for the year 2002. These sections operate as a dual-dual freeway facility: divided inner and outer lanes. At these locations, the inner lanes have the special characteristic of being for passenger cars only (homogeneous traffic). The selected sections, therefore, offer a very good opportunity to compare the crash experience between passenger car-only and mixed traffic rural freeway facilities. The results of the study show that outer lanes experience more crashes, both when raw numbers are used and exposure is included into the analysis. It shows that truck-related crashes contribute significantly to the total number of crashes on the outer lanes. In fact, trucks are overinvolved in crashes given the exposure on these sections. Even though the outcome of this study suggests that separating truck traffic from passenger cars for freeway facilities improves safety, further work is needed to understand the contributing factors leading to truck-related crashes in the outer lanes.