MnDOT and Local Road Research Board

This report presents the results of a two-year field study on the performance of erosion control products under natural and artificial rainfall conditions. Vegetation, runoff, and erosion data were collected at a newly constructed roadway. Runoff and erosion data were gathered using natural rainfall events and using a rainulator to spray water onto the surface. Treatments included a wood fiber blanket, a straw/coconut blanket, a straw blanket, a bonded fiber matrix, and disk-anchored straw mulch for natural rainfall events. For the rainulator events, a bare soil treatment also was used. Biomass, percent cover, and species composition also were measured at the research site. Five runoff events from natural rainfall were measured and revealed very little difference in sediment production between the straw, straw/coconut, and the wood fiber blankets. These blankets had approximately one-tenth the erosion that was observed for the straw-mulch plots. The impact of the erosion control treatment was substantial for early season artificial events. The sediment loading rates from the blankets and bonded fiber matrix plots were roughly one hundred times smaller than the bare soil plots and 10 times smaller than the straw mulch plots. For late season events, the erosion from these products were approximately one-half of that from straw mulch treatments.

This research explores the potential safety effects of dynamic signing at rural horizontal curves. It accomplishes this by asking two key questions. First, is there a relationship between a vehicle's speed on the approach to a curve and the ability to successfully navigate the curve? Second, is there a difference between static and dynamic signing in the ability to reduce the speed of high-speed vehicles? Researchers assembled an off-the-shelf hardware and software package and deployed it at a four-degree curve along CSAH 54 in rural Dakota County. If purchased new, the package would cost about $50,000; however, an agency could deploy the components necessary to perform dynamic curve warning (a changeable message sign and radar unit) for approximately $10,000. The field test collected vehicle speed data for about 2,600 vehicles. In addition, researchers tracked and videotaped 600 vehicles. The data suggest, and statistical tests confirm, that the initial speed of a vehicle before entering a curve does have a statistically significant effect on the probability of successfully navigating through the curve. The data also indicated that the overall effect of the dynamic curve warning system on vehicle speeds is relatively small. However, the dynamic system had a much greater effect on high-speed vehicles than the static curve warning sign and the dynamic system significantly improved the ability of the high-speed vehicles to successfully navigate through the curve.

This report presents information on the various types of available sign sheeting material and summarizes information on signing terminology, retroreflectivity and the aging problem, signing materials, life-cycle costs, best management practices, and sign management systems. A review of the existing signing materials indicates that some of the higher-priced and higher-quality sheetings have lower life-cycle costs than the less expensive sheetings. As a result, long-term cost savings can be achieved by using the material that is initially more expensive. In addition, it was found that the higher-quality sheetings provide better detection and recognition for drivers.

Recent changes in laws regarding the use of volatile organic compounds impact the type of pavement marking material that many communities use to mark or delineate their roads. This report presents information on the various types of pavement marking materials available and summarizes information on pavement marking material terminology, the various types of pavement marking materials, their durability, and their retroreflectivity. The report explains changes in formulas relating to laws regulating the use of volatile organic compounds, as well as the impacts of those changes. Additionally, it includes a list of best management practices. This report indicates that for low-volume roads [annual average daily traffic (AADT) of 10,000 or less], a conventional product, such as paint, may be the most cost-effective material. For roadways with higher volumes (AADT of 10,000 or more), a more durable product, such as epoxy, tape or thermoplastics, may be more cost effective and may reduce worker exposure to traffic.

This report discusses the major technical issues, environmental impacts, and economic factors for the design and analysis of an electrical pipeline system. Researchers reviewed the history and related work on pipeline transportation, as well as linear electric motors, analyzed basic components for an electrical pipeline system, and devised and compared several possible system configurations. They selected a moving-primary linear induction motor configuration for medium- to long-range freight transportation. For this system configuration, preliminary designs are conducted on capsule structure, linear induction motor units, and pipetubes. A comprehensive computer simulation program is coded based on governing equations of motion. Researchers conducted system operation design and simulations by using the computer program.

This report presents the results of numerical and experimental investigations to determine the causes of prestressed concrete girder end cracks. The cracks, which develop during the flame-cutting release process, result from the restraining effect of unreleased strands as the girder shortens from the partially transferred prestress and from shear stresses generated by the cutting order of the strands. Researchers examined several methods to eliminate the cracks, such as making changes to the strand cutting pattern, debonding some of the strands in the end regions, and increasing the slope of the top surface of the bottom flange. Implementation of the first two of these methods in the field proved successful.

This report describes a system for monitoring bicycle activity in sequences of gray scale images from a stationary camera. Applications for such a system include determining the use and congestion of bicycle paths. The output of the system is a count of the number of bicycles detected in the image sequence. The system uses a simple model of two circular objects separated by relatively known distance, with four levels of abstraction: raw images, blobs, edge images, and the bicycle model. The system was implemented on a dual Pentium computer equipped with a Matrox imaging board and achieved a peak performance of eight frames per second. Experimental results based on outdoor scenes show promising results for a variety of weather conditions.

This research applied wave band and computer vision methods to automatically count vehicle occupants in the High Occupancy Vehicle (HOV) lane at a high level of accuracy. The research showed that use of near-infrared bandwidth offers potential as a method for developing an automatic vehicle occupant counting system. Near-infrared only can produce images when looking through glass, but not metal or heavy clothes, which limits its accuracy in counting children or occupants resting in vehicles. The mid-infrared camera did not produce clear images at highway speeds. The next step involves additional research into a working device that can count vehicle occupants reliably, including analysis of device performance with more types of vehicles, passengers in the back seats, children in car seats, and passengers lying down.

This study evaluates the use of seal coating as a method to protect bituminous pavements from oxidation, water infiltration, and raveling. The Minnesota Department of Transportation (Mn/DOT) applied seal coating to a roadway segment of Trunk Highway 21 in August 1998. The report outlines optimal requirements for the application of seal coat. Cost comparisons of the test sections are also presented. Mn/DOT will continue to examine the test strip for performance and provide regular updates until the strip's condition requires reconstruction or overlay.

In this project, landscape architects, architects, and urban design professionals explored land use opportunities and challenges in the six neighborhood light rail stations of South Minneapolis' Hiawatha Corridor. They studied the Cedar Riverside, Franklin Avenue, Lake Street, Thirty-Eighth, Forty-Sixth, and Minnehaha station areas, analyzing land use patterns, pedestrian and vehicular routes, current zoning, destinations, and potential development sites. They gathered comments from residents in public meetings. Based on the analysis and public feedback, the researchers identified potential development scenarios for each station area. This report summarizes those scenarios.