Aldo Fabregas

Landscaping of highway medians and roadway safety at unsignalized intersections

Well-planted and maintained landscaping can help reduce driving stress, provide better visual quality, and decrease over speeding, thus improving roadway safety. Florida Department of Transportation (FDOT) Standard Index (SI-546) is one of the more demanding standards in the U.S. for landscaping design criteria at highway medians near intersections. The purposes of this study were to (1) empirically evaluate the safety results of SI-546 at unsignalized intersections and (2) quantify the impacts of geometrics, traffic, and landscaping design features on total crashes and injury plus fatal crashes. The studied unsignalized intersections were divided into (1) those without median trees near intersections, (2) those with median trees near intersections that were compliant with SI-546, and (3) those with median trees near intersections that were non-compliant with SI-546. A total of 72 intersections were selected, for which five-year crash data from 2006-2010 were collected. The sites that were compliant with SI-546 showed the best safety performance in terms of the lowest crash counts and crash rates. Four crash predictive models-two for total crashes and two for injury crashes-were developed. The results indicated that improperly planted and maintained median trees near highway intersections can increase the total number of crashes and injury plus fatal crashes at a 90% confidence level; no significant difference could be found in crash rates between sites that were compliant with SI-546 and sites without trees. All other conditions remaining the same, an intersection with trees that was not compliant with SI-546 had 63% more crashes and almost doubled injury plus fatal crashes than those at intersections without trees. The study indicates that appropriate landscaping in highway medians near intersections can be an engineering technology that not only improves roadway environmental quality but also maintains intersection safety.

A systems analysis framework to optimize the utilization of electric vehicles at military facilities

The U.S. Department of Defense (DOD) is the worlds largest consumer of petroleum, a commodity whose price volatility makes budget planning extremely difficult. A significant amount of DODs oil consumption is attributable to its massive fleet of non-tactical vehicles - sedans, trucks and vans used for official duties at installations around the world. Federal statutes require the U.S. military to incorporate alternative-fuel vehicles, including those powered by electricity, in this fleet. This paper uses discrete event simulation built on real-world data from a fleet of sedans at an Air Force base to explain how the U.S. military can procure optimal numbers and types of electric vehicles (EVs) that will maximize financial savings while still meeting mission requirements. Output from simulated operation of the optimized fleet is then used to analyze the sensitivity of operating expense with respect to gasoline and electricity prices. This framework illuminates the path to widespread EV adoption without the time, expense and risk of committing physical assets.

Embedded system design of an advanced illumination measurement system for highways

Roadway illumination is a vital component of safety while driving during the night. There are regulations in place to ensure all publicly maintained roads are properly lit, but the validation process is too time consuming, costly, and dangerous for adequate data collection studies. This work is aimed toward remedying this problem by creating an Advanced Lighting Measurement System (ALMS) capable of recording illumination readings while traveling at normal driving speeds. This solution is based on the Arduino Uno development board, a cost effective yet powerful microcontroller. The proposed embedded system consists of Ariduino Uno microcontroller, Distance measurement instrument, USB module, event logger, GPS module, light meters, and microSD module. This work involves collecting data along 100 centerline miles of Florida roadways and converting the resulting illumination readings into GIS format, allowing them to be included in the roadway database of the Florida Department of Transportation. By including this data the FDOT will be able to repair poorly lit corridors and will be aware of possible safety concerns. The illumination values recorded by the ALMS have been validated and verified as an accurate replacement for conventional lighting measurements. The system requires minimal user interaction and rapidly speeds up illumination measurement along highways.

Application-driven traffic sensor system acceptance tests for intelligent transportation systems

Transportation agencies strive to keep people and goods moving. Operation and maintenance of transportation infrastructure is key to accomplish their objectives. Intelligent Transportation Systems (ITS) applications rely on massive detection grids that collectively demand significant maintenance resources. Resource constraints force transportation agencies to look for innovative ways to optimize their operational and maintenance costs while serving their users at intended performance levels. This paper presents a Systems Engineering (SE) view to derive traffic detection sensor requirements for components and subsystems based on application-specific needs. The goal of the approach is to obtain stakeholders view of an acceptable performance based on the top-level functionality for a given ITS application. The proposed approach uses a simulation model to obtain quantitative evidence of the minimum performance for the detection system.

Requirements and decision model for a taxiway route support system

Airports, are major components of the global transportation network and are the subject of continuous operational improvements. Commercial aviation industry has experienced substantial growth in the last decades. This booming demand generates economic benefits, however, it also increases the congestion levels at airports. While demand is a source of recurrent congestion, it is very common experience other forms of non-recurrent congestion. Extreme weather events, equipment failure and security threats are commonly encountered sources of non-recurrent congestion. This work presents the application of the systems engineering process to build a decision support system for ground traffic control. The proposed model should be able to assist ground traffic control operators to route planes in the taxiways in a system-optimal fashion. Business use cases, requirements, model verification, are presented. The proposed model is able to handle both, recurrent and non-recurrent congestion at the operational level. The proposed model is tested for a single runway airport case with moderate to heavy degree of congestion. Percentage of congestion effectively reduced ranged from 10% to 14%, depending on taxiway geometry. Results are encouraging enough to establish the proposed model as a feasible concept and, a practical system can be developed with further research and development. In addition, non-functional requirements at the management level allow using the model to determine capacity, and measure operational performance.

Planning and Design for Prevention of Incorrect Turns onto Highway-Rail Grade Crossings

In recent years, a number of injuries and fatal collisions have occurred at certain highway-rail grade crossings located adjacent to highway intersections, driveways, or freeway on-ramps. Some guide signage, pavement markings, and other traffic control devices currently present at the crossings may have confused drivers and caused them to turn onto the railroad tracks rather than at the nearby intersections, driveways, or freeway on-ramps. Due to limited research in this new area of prevention of incorrect turns at highway-rail grade crossings, a research project was sponsored by the National Center for Transit Research and Florida Department of Transportation to seek cost-effective solutions. This paper first provides an intensive literature review to identify available sources of information and best practices throughout the world for innovative and cost-effective infrastructure treatments. It then presents analysis of the contributing causes of crashes that occurred in the past and offers a set of countermeasures for planning and design aimed at improving incorrect turns at highway-rail grade crossings.

Development of Resource Allocation Strategies for Operating and Maintaining Traffic Signal Systems

Functional vehicle detection and signal system communication are essential for a traffic signal system to execute its intended coordinated signal timing plans. The degradations of vehicle detection and signal system communication could impose barriers to successful operations of a traffic signal system. To achieve and maintain an acceptable operational level set by a traffic agency, an agency has to prioritize its resource allocation. This paper first introduces the concept of traffic signal system performance. It defines a traffic signal system degradation index which measures the proportion of increased travel time attributable to failures in detection and communication components with respect to the total observed travel time of a traffic signal control section. The paper uses the degradation index and traffic simulation to evaluate the effectiveness of major strategies to improve vehicle detection and signal system communication. These strategies include upgrading detection technologies, improving the responsiveness to detection and communication repair work, providing adequate training, increasing the frequency of inspection, and installing a global positioning system (GPS) clock to maintain synchronization of the time clock in the controller. Finally, recommendations for optimal allocation of operation and maintenance resource allocation strategies for traffic signal systems are provided.

Assessment of a Flashing Yellow Arrow Signal Implementation Using Gap Acceptance Measures

The use of flashing yellow arrow (FYA) displays for protected-permitted left turn (PPTL) operations has been increasing in recent years. With its inclusion in the MUTCD, more traffic agencies will likely adopt FYA for PPTL operations in the future. The intent of FYA is to replace traditional green ball displays to make drivers more cautious when making permissive left turns. In this case study, a before-and-after study of an FYA deployment was performed. The study used gap acceptance as a short-term safety measure to evaluate the FYA deployment under different traffic conditions. It was found that under similar low to moderate traffic conditions, by implementing FYA, most drivers accepted longer gaps to make their permissive left turns, hence improving the safety. No noticeable benefits from FYA were found under heavy opposing traffic conditions when available gaps were short. Opposing traffic volumes also have a significant impact on gap acceptance behaviors.

Cost Benefit Analysis of Freeway Service Patrol Programs: A Case Study in Florida

Floridas Road Rangers provide free highway assistance services during incidents on Floridas roadways to reduce delay and improve safety for the motoring public and responders. This paper presents the research results from a recently completed study to describe and quantify the benefits derived from the Road Ranger program. The Freeway Service Patrol Evaluation (FSPE) model, developed by the University of California at Berkeley, was used to quantify the benefit-cost (B/C) ratio using a variety of data from the Florida SunGuide database for the year 2010. The benefits (delay and fuel savings) of the Road Ranger program were about

The Timing to Retime and Maintain Traffic Signal Systems

135.3 million in total, and the costs (contract) were about