Roads

Showing surfacing of roads and mileage between cities; compliments of Conners' Florida Highway, West Palm Beach, Fla.

Due to the presence of deep deposits of organic soils at shallow depths, roadways in western Palm Beach County, FL show premature distress and failure requiring frequent rehabilitation. In an effort to develop effective mitigation strategies, 24 test sections, containing various types of pavement reinforcing materials, were constructed during Fall of 2008. This study presents a forensic investigation and dynamic characterization of reinforced asphalt cores obtained from SR15/US98 for evaluating the uniformity of test sections, qualitative comparisons, and developing empirical models for predicting permanent deformation and material damage with stress cycles simulating traffic loading.

Highway Capacity Manual (HCM) 2010 methodology for freeway operations contain procedures for calculating traffic performance measures both for undersaturated and oversaturated flow conditions. However, one of the limitations regarding oversaturated freeway weaving segments is that the HCM procedures have not been extensively calibrated based on field observations on U.S. freeways. This study validates the HCM2010 methodology for oversaturated freeway weaving segment by comparing space mean speed and density obtained from HCM procedure to those generated by a microsimulation model. A VISSIM model is extensively calibrated and validated based on NGSIM field data for the US 101 Highway. Abundance of the NGSIM data is utilized to calibrate and validate the VISSIM model. Results show that HCM methodology has significant limitations and while in some cases it can reproduce density correctly, the study finds that speeds estimated by the HCM methodology significantly differ from those observed in the field.

In the last decades, population growth has been outpacing transportation infrastructure growth, and today's transportation professionals are challenged to meet the mobility needs of an increasing population. The effectiveness of the transportation system is an essential constituent of people's daily lives as they commute between different points of interest. Studies show that at many highway junctions, congestion continues to worsen, and drivers are experiencing greater delays and higher risk exposures. Engineers have very little resources to handle this increase in population. One solution to resolve and alleviate congestion due to increasing traffic volumes and travel demands relies in implementing alternative designs. This approach will help traffic engineers determine which design will be the most appropriate for a particular location. This study compares and evaluates the Diverging Diamond Interchange (DDI), which is an unconventional design, to Partial Cloverleaf (ParClo) types A4 and B4 interchange designs by evaluating different Measure of Effectiveness (MOEs). Using microsimulation platform AIMSUN, each interchange type was evaluated for low, medium and high traffic flows. The analysis revealed that the DDI with four through lanes performed better than the ParClo A4 for unbalanced conditions, the DDI with six though lanes had similar results as the ParClo B4 for very high volumes. In terms of queue, the DDI design had a much better performance. The results from the analysis help in providing guidelines to the decision makers for selecting the best alternative in terms of performance.

The rapidly and significantly growth of the population in the United States has caused expansion of the urban areas to accommodate more residential facilities.. Thus, the demand for more efficient intersection designs is a high priority, as wasted fuel and travel time increases each year. A new method to solve the congestion issue is the creation of unconventional arterial intersection designs (UAID). The objective of this study is to compare the operational and environmental performance of three UAIDs called Left-turn Bypass, Diverging Flow, and Displaced Left-turn intersections. This study will evaluate the UAIDs in the isolated manner and then compare the intersections in a network using an existing corridor in the state of Florida. The microscopic simulation platform VISSIM v. 5.10 will be used to test different scenarios. The results indicated that the Displaced Left-turn consistently reports better results for average delay of less than 20 seconds per vehicle.

This study describes analytical model as one innovative way to simulate Light Rail Transit (LRT) operations and calculate vehicular, transit and person delays at LRT crossings through Microsoft Excel. Analytical model emulates LRT trajectories from field and use these trajectories to clearly define train and car phases through Visual Basic for Applications (VBA) logic, which is part of analytical model. Simulation of train trajectories and calculations of delays were done for different LRT strategies and estimated roadway condition, Testing and validation of analytical model were performed in one case study in Salt Lake City (UT). Results show that analytical model is capable of emulating LRT trajectories and estimating delay at isolated LRT crossing. However, analytical model is not capable of simulating different train strategies at two or more LRT crossings, at the same time. Finally, extracted strategy provides savings from $100.000 to $200.000 in study area, on annual basis for projected year.