Institute for Transportation

About the research

Objective
The objective of this project was to provide Aurora member agencies with an automated means of problem identification and reporting for their RWIS equipment. Functionality of an existing Minnesota Department of Transportation system was used as a base to design the desired system. The end result of this project was a web-based solution that each Aurora member agency could choose to host or have someone host for a fee.

About the research

Objective
This project looked to determine under what condition frost on bridge decks creates slippery conditions and then to develop a forecast model that can predict when this may occur at a site or across a region. Work under Phase 1 is complete. Remaining work was completed under the second phase, Project 2004-05.

About the research

Objective
This research involved a third and final phase of the intelligent image-based winter road condition sensor research effort. From the beginning, the goal of this third phase was to use one road condition classification system on all camera sites in Sweden. When researchers discovered in this phase that the accuracy was far too low when the equipment was moved to new sites, it was soon realized that the potential benefit disappeared immediately. The first two phases of the project had shown significant promise, and this third phase continued research and movement of the test site to new locations in order to acquire additional research data. Three neural networks were used in the field tests: one for day, one for night, and one combined day/night network. Initial tests were done in Matlab to get information about the performance of the three different neural networks. Test one showed that the classification was very correct even within a reasonable confidence value. It was also noted that in the current situation, only two types of road conditions, dry and snow, were being classified. In the 2005-2006 winter, up to five classes of road conditions were able to be detected, and a second camera was set up to verify the accuracy of the first. Unfortunately, as noted above, the field image classification system was far too low in accuracy to be acceptable.

About the research

Objective
The objective of this project was to conduct a fourth national winter maintenance meeting to share research results from the peer exchanges held in 2007, 2009, and 2011.

About the research

Objective
The objective of this project was to conduct a fifth national winter maintenance meeting to share research results from the peer exchanges held in 2007, 2009, 2011, and 2013.

About the research

Objective
The first objective of this project was to collect member specifications for the construction of, maintenance of, and/or forecasts at RWIS stations, then to develop a database of these specifications. The second objective was to survey the agencies who had provided specifications to better document and understand the issues associated with administering the various contracts.

About the research

Objective
This project involved development of an outreach slide presentation that captures the advances and improvements in road weather forecasting and nowcasting. As the National Weather Service modernizationmoved into full implementation, some recognized the potential impact this could have on daily operations, but many others were not convinced. Therefore, there was a need to show the rest of the transportation community the difference between the old and new through simple presentation material. The primary audiences for this presentation were state and local DOT staff and managers.This project involved development of an outreach slide presentation that captures the advances and improvements in road weather forecasting and nowcasting. As the National Weather Service modernizationmoved into full implementation, some recognized the potential impact this could have on daily operations, but many others were not convinced. Therefore, there was a need to show the rest of the transportation community the difference between the old and new through simple presentation material. The primary audiences for this presentation were state and local DOT staff and managers.

About the research

Internal curing (IC) is a practical way of supplying additional curing water throughout the concrete mixture. This water can improve the hydration of cement, reduce autogenous shrinkage, and improve durability. The purpose of this document is to provide guidance for the development of project specifications for internally cured concrete projects. The guidance in this document is designed to supplement the agency’s standard specifications for concrete pavement. If the standard specifications are outdated, modifications other than those provided in this document may be necessary to produce a high-quality, long-lasting concrete. This document contains IC specification language, references to IC resources, references to IC instructional videos, and references to tools that can be used for IC of concrete or providing quality control.

About the research

The objectives of this study were to develop guidance for engineers on how implements of husbandry loads are resisted by traditional bridges, with a specific focus on bridges commonly found on the secondary road system; provide recommendations for accurately analyzing bridges for these loading effects; and make suggestions for the rating and posting of these bridges.

To achieve the objectives, the distribution of live load and dynamic impact effects for different types of farm vehicles on three general bridge types—steel-concrete, steel-timber, and timber-timber—were investigated through load testing and analytical modeling. The types of vehicles studied included, but were not limited to, grain wagons/grain carts, manure tank wagons, agriculture fertilizer applicators, and tractors.

Once the effects of these vehicles had been determined, a parametric study was carried out to develop live load distribution factor (LLDF) equations that account for the effect of husbandry vehicle loads. Similarly, recommendations for dynamic effects were also developed.

Finally, suggestions on the analysis, rating, and posting of bridges for husbandry implements were developed.

The third volume of the report contains six appendices that include the 19 mini-reports for field tested and analytically modeled steel-concrete, steel-timber, and timber-timber bridges, the farm implement and bridge inventories for the project, and survey responses.

About the research

Winter highway maintenance is an annual multi-billion dollar operation aimed at improving the safety and mobility of the highway system. To help the winter highway maintenance agencies optimize the usage of resources, it is important to develop a performance measurement system that can evaluate how well maintenance activities have been performed. In Iowa Highway Research Board Project TR-491, researchers developed a performance measure based on average vehicle speed, which takes into account severity of the storm. The model uses six categorical variables to define a storm and compute the acceptable traffic speed drop.

A previous Iowa Department of Transportation (DOT) agreement developed a sequential Bayesian dynamic model based on the model in TR-491, which is capable of predicting the acceptable drops during the storm, and allow uncertainty in input variables (sensor measurements) to propagate into uncertainty in speed reduction. One limitation of the sequential Bayesian model is that its uncertainty measure does not account for model uncertainty and the uncertainty in human-weather interaction. The model in TR-491 is based on survey of expert opinion, and its uncertainty is not considered in the original development and our follow up work. The uncertainty in human behavior under different weather conditions is also not considered due to lack of time.

The Iowa DOT is interested in refining this sequential Bayesian model to produce more accurate real-time prediction of traffic speed drops with better uncertainty measures so that it can be used to evaluate the performance of snow/ice removal efforts and the effectiveness of different snow removal methods. Ultimately, the DOT is interested in using this model to help managers reallocate resources to optimize objective functions such as minimizing the total costs or the speed drops. The DOT is interested in developing a dynamic model capable of predicting in real-time acceptable drops in traffic speed on highways during major weather events with realistic uncertainty measures. The primary usage of such model is to evaluate the performance of highway winter maintenance operations and optimize resource allocation.

The researchers developed a model to relate weather variables to traffic flow changes at a local level. Weather station data and maintenance crew reports were used to develop an empirical adaptive stochastic model using a Bayesian formulation. Data from early time segments provide a prior quantification of the expected effects of weather variables on traffic speed over subsequent time segments. Data in the next time segment are then used to adjust these quantifications to reflect observed traffic speeds during that period. Thus, rather than explicitly determining numerous temporally dependent interactions, the main effects associated with key factors are allowed to undergo small shifts over time to fit the data. The model incorporates an autoregressive error structure to reflect temporal dependencies in observations that occur at reasonably high frequencies.