Recent ICT/IDOT Reports Online

The following reports from recently completed IDOT-sponsored projects are now available on ICT’s website …

R27-142: Evaluation of Software Simulation of Road Weather Information System. A road weather information system (RWIS) is a combination of technologies that collects, transmits, models, and disseminates weather and road condition information. These data are transmitted to automated warning systems, traffic operations centers, emergency operations centers, and road maintenance facilities for decision support. The Enhanced Integrated Climatic Model (EICM) is a computerized heat and moisture flow model that simulates changes in pavement and subgrade properties. Using the EICM as a software‐based RWIS can “virtualize” the data that would be gathered by conventional RWIS hardware and software systems. The software‐based RWIS stations would provide current conditions as well as pavement temperature forecasts to supplement or replace hardware in the RWIS network. The objective of this study was to evaluate the use of the EICM to determine pavement surface temperature for winter maintenance operations. Data analysis showed that, when the pavement materials are used at the correct thickness and recommended default values are used for material types, a reasonable pavement surface temperature prediction can be obtained. Using these recommended default values for thermal conductivity, heat capacity, and shortwave absorptivity results in a reasonable model.

R27-160: Illinois Highway Materials Sustainability Efforts of 2015. This report provides a summary of the sustainability efforts of the Illinois Department of Transportation (IDOT) in recycling reclaimed materials in highway construction during calendar year 2015. This report meets the requirements of Illinois Public Act 097‐0314 by documenting IDOT’s efforts to reduce the carbon footprint and achieve cost savings through the use of recycled materials in asphalt paving projects. Research efforts undertaken and those that will have a future impact on IDOT’s sustainability efforts are also highlighted.   In 2015, 2,009,972 tons of reclaimed or recycled materials, valued at $59,715,613, were used in Illinois highways. It was estimated that the substitution of virgin materials with reclaimed and recycled materials resulted in a net reduction of carbon dioxide emissions of 132,247 tons.

R27-SP30: Speed Harmonization—Design Speed vs. Operating Speed. When the actual operating speed on roads exceeds the design speed, which is common on rural highways, the roadway design may become problematic from a safety point of view. This report presents a new methodology that summarizes the relationship between design speed and operating speed, as well as the safety impacts of various geometric elements. A comprehensive literature review and a series of interviews with Illinois county engineers were conducted to summarize the current roadway design and maintenance practices and their impacts on Illinois roadway safety. An integrated modeling framework that includes modules for geometric design simulation, operating speed‐profile prediction, and crash rate prediction, is proposed. A benefit–cost analysis was also developed to quantify the economic benefits of various strategies for roadway safety improvement. All models were programmed into an Excel VBA‐based computer tool to facilitate decision making. The outcome of this project may be suitable for implementation in a wide range of application contexts.