Toll plaza designs have implemented electronic toll collection and other technologies to improve toll systems; however, an increase in crashes has appeared with these improvements. To study safely the pertinent aspects of driver behavior in toll plazas with electronic toll collection, a cockpit driving simulator housed at the University of Puerto Rico at Mayagüez was used. Specifically, in this study a comparison was made of two configurations of the signs that indicated the corresponding speed limit and toll station for each lane in the area before the toll plaza. One configuration corresponded to the current condition of the signage in Puerto Rico, with signs located at the roadside; the second configuration presented a proposed overhead signage treatment. A representative group of 20 subjects was selected to test the effectiveness of the two signage configurations on the approach zone leading to the toll plaza, calculating the standard deviation of roadway position, speed, and acceleration noise in five zones. The behavior of drivers using the proposed signage configuration appeared to be safer than the behavior of drivers following the current signage configuration. Specifically, at each of five zones in which behavior was sampled on the approach to the toll plaza, drivers using the proposed configuration changed lanes more smoothly and reduced their vehicles’ velocity more when approaching the toll plaza. Nevertheless, there was no significant difference between configurations in acceleration noise. The results of this study provide strong evidence that driving simulators can be used effectively to identify efficient and inexpensive alternative signage configurations at toll plazas.

Driving simulators have been widely used in transportation research and have potential applications for toll plaza safety research. The University of Puerto Rico at Mayagüez (UPRM) and the University of Massachusetts, Amherst (UMass-Amherst) performed a collaborative investigation using driving simulators to evaluate drivers’ behavior in two toll plazas with different signage and lane configurations that operate under the U.S. jurisdiction. The studied toll roads were the Caguas South Toll Plaza in Puerto Rico and the West Springfield Toll Plaza in Massachusetts. The major safety issues identified in both toll roads were unexpected lane changes, sudden vehicle stops, and variable speed patterns. The purpose of this study was to exchange research scenarios between UPRM and UMass-Amherst to test drivers who were unfamiliar with the areas of the study and enlarge the scope. Assuming that the patterns of behavior were similar, the results would suggest that drivers’ behaviors from different regions depend largely on the geometry of the toll plaza and not on the driving culture particular to a region. This study will greatly add to the utility of driving simulator studies because the results reported from one region and one toll plaza arrangement should generalize to other regions around the country and to territories. Results show that familiar drivers had a better driving performance, with respect to variability of lane position, when compared with unfamiliar drivers. However, the proposed treatments for each toll plaza improved road safety for both familiar and unfamiliar drivers.

Abstraa -This paper describes the development of software tools for the analysis of chaos in power electronics systems. This project was motivated by potential contributions of chaos theory in the design, analysis and control of power electronics circuits. Nonlinear analysis software and computer programs were used for the detection and analysis of chaotic components. Simulations of power electronics &-vices were performed using commercially available circuit analysis packages. The voltage and current time series obtained from the circuit analysis were studied using the nonlinear analysis tools developed for this project as well as existing nonlinear analysis programs. The results of the nonlinear analysis can be used to design and implement better mitigating and control techniques for the circuits under study. Chaotic dynamics provide an alternate representation that can lead to better designs and new ways to explain nonlinear behavior in power electronics circuits. There is also a great pedagogical value in complementing the traditional representation of power electronic circuits with alternate models.

Innovations on intersection design have been the focus of recent developments in the US and around the world. The second installment of the Every Day Counts initiative (EDC-2) from the Federal Highway Administration (FHWA) promoted five new intersection designs. One of them was the Diverging Diamond Interchange (DDI). This innovative design has been implemented in several cities in the US to improve operations and safety. Puerto Rico is currently building its first DDI in the intersection of an arterial street and a freeway in the Municipality of Gurabo. This paper discusses the main characteristics of the DDI and presents a design framework from conception to implementation. This framework considers the geometric, environmental, and cultural influence in the design of a DDI, while also paying attention to the influence of non-motorized users and the continuous evaluation of the intersection by using driving simulation as part of the effective project implementation. Other topics discussed include safety evaluation, signaling, traffic influence, and the use of driving simulation into the determination of operational safety at a DDI. Also, the comparison between the conventional diamond interchange and the DDI, potential DDI issues from an operational point of view, and the objectives or goals of this type of intersection design are presented. A discussion of the benefits of using a driving simulator as a tool to evaluate a DDI and the importance of the data gathered in the process are also explained. Details of the implementation of this framework in Puerto Rico are presented as concluding remarks.

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