Janson, Michael

Various costs and benefits are incurred while performing winter maintenance operations. However, a summary of these costs and benefits for different maintenance scenarios has not been compiled to date. This report summarizes past work that documented the quantified and non-quantified costs and benefits of three different winter maintenance strategies of interest; use of abrasives, salts and other chemicals in solid and liquid forms, and snow plows. Basic strategies were defined as plowing and use of abrasives, intermediate strategies were defined as the use of rock salt and salt brine (NaCl), and advanced strategies were defined as the use of corrosion inhibitors, inhibited salt brine, magnesium chloride, calcium chloride, and blended products. These approaches employ different components, both in terms of equipment as well as materials. Some components of the various strategies have better cost and benefit information available than others. This is particularly true of sanding/abrasives and salting. Other, more recently developed and employed approaches and materials have more limited cost and benefit information published. There are also a number of different environmental impacts associated with different components of each maintenance strategy. Using information gained from the literature review, surveys, and interviews summary benefit-cost matrices were developed for various winter maintenance strategies. Information and data gap analysis has aided in identification of areas for recommended research. This document is intended for use by transportation agencies, such as by maintenance supervisors, to aid in the decision making process in terms of the selection of winter maintenance strategies used to achieve a prescribed LOS.

While High Occupancy Vehicle (HOV) lanes have been used for decades as a strategy for mitigating congestion, research has shown that they are not always effective. A 2001 study of the I-394 and I-35W HOV lanes in Minnesota found that the HOV lanes were on average underutilized, moving fewer people than the General-Purpose Lanes (GPL) even with the increased number of passengers per vehicle. To address the issue of underuse, in 2003 the Minnesota Legislature authorized the conversion of the I-394 HOV lanes into High-Occupancy Toll (HOT) lanes, named the MnPASS Express Lanes. The MnPASS lanes operate using a fully dynamic pricing schedule, where pricing is dictated by the level of congestion in the HOT lane. To better understand the nature of HOT lanes and the decisions of their users, this study explored the possibilities for a microscopic traffic simulation-based model of HOT lanes. Based on a series of field studies where the price of the toll was changed while observing changes in demand in the HOT lane, models describing the lane choice behavior of MnPASS users were developed and calibrated. These models interfaced with the traffic simulation software Aimsun through a number of extension modules and tested on the two MnPASS corridors of I-394 and I35W corridors in the west and south suburbs of Minneapolis, Minnesota. The integrated HOT simulation tool was also used to develop and test a number of alternative pricing strategies including a more efficient version of the current strategy.

Conventional methods for detecting vehicles for permanent travel monitoring stations have relied on detecting physical attributes of vehicles without correlating these with the specific vehicles and/or motor vehicle freight operators. However, by using a license plate reader camera, information can be gathered and cross referenced to other known data related to the specific vehicle assigned to the license plate. This could provide additional tools for enforcing overweight vehicles or targeting enforcement communication with freight carriers that consistently violate weight limits. The analysis conducted during this project compared machine-read license plates to manually collected license plates. The license plates were read as vehicle travelled highway speeds in a generally uncontrolled environment. Analysis is also provided that correlates hours of direct sunlight with accuracy of the automated reader. A second analysis was conducted as an effort to improve the accuracy of the Minnesota Department of Transportation's weigh-in-motion classification scheme and bring it in line with the Department's classification scheme for automatic traffic recorder stations (sites with axle-based detection that do not collect weight information).

The Minnesota Local Road Research Board, MnDOT, and SRF performed an evaluation of a portable weigh-inmotion (WIM) system at several locations throughout Minnesota. The system was developed at the University of Minnesota-Duluth and offers roadway designers a low-cost method for obtaining vehicle load distribution data across the state's road network. To deploy the system, the weigh pads of the system were temporarily affixed sensors across the roadway lanes. As vehicles passed over the weigh pads, pressure sensors within the pads detected the weight of vehicles and the system recorded the data for later analysis. Traditional methods for travel monitoring generate traffic volume and classification data, but weigh-in-motion systems give designers a more accurate idea of current and projected traffic loading demands. SRF's testing provided implementation refinements that were incorporated into the system. During the two-year deployment process, the portable WIM system was installed under a wide array of environmental conditions to demonstrate the system's capabilities. Data generated by the system was analyzed. The Final Report details system deployment, calibration, and system accuracy.