Didier Valdés

Driving Simulation of the Safety and Operation Performance at a Freeway Toll Plaza

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.

Comparative Analysis of Toll Plaza Safety Features in Puerto Rico and Massachusetts with a Driving Simulator

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.

Work in progress — introducing graduate students to ethical deliberation and Case Analysis in Research Ethics

This paper describes a work in progress focused on graduate education activities that will immerse graduate students in Research Ethics. The project aims to develop ethical awareness and basic skills in moral deliberation. Because these workshops will verify common concerns in Research Ethics, it is expected that they will also produce results valuable to other institutions. The ethical deliberation workshop is the second in a series of four workshops introducing the students to the basic issues in Research Ethics. The moral deliberation workshop will be followed by a Case Analysis Workshop which includes the analysis of famous cases of Research Ethics misconduct as well as hypothetical cases that are likely to be encountered in the studentpsilas career. The hypothetical cases include situations related to fabrication, falsification and plagiarism.

Operational and Safety Analysis of Signage and Pavement Marking Treatments in Puerto Rico Dynamic Toll Lane Using a Driving Simulator

The Puerto Rico Dynamic Toll Lane (DTL) is a managed lane system for light traffic that combines congestion pricing, reversible lanes and a Bus Rapid Transit system within the median of freeway PR-22. This research aims to evaluate if modified signage and the addition of in-lane pavement markings could help improve operational and safety aspects of the DTL using the UPRM driving simulator. The performance measures used to evaluate driving behavior were vehicle average position, average speed and acceleration noise, which has been used as a surrogate measure to evaluate safety. A total of four virtual scenarios were studied using time of day and traffic flow as independent variables to evaluate two configurations: existing conditions (Configuration 1) and proposed conditions using modified signs and pavement marking treatments (Configuration 2). However, results of the study indicates that there were no significant differences between configurations for the performance measurements evaluated.