Development of a Computer Controlled Underbody Plow: TR412, Final Report, January 2006

Underbody plows can be very useful tools in winter maintenance, especially when compacted snow or hard ice must be removed from the roadway. By the application of significant down-force, and the use of an appropriate cutting edge angle, compacted snow and ice can be removed very effectively by such plows, with much greater efficiency than any other tool under those circumstances. However, the successful operation of an underbody plow requires considerable skill. If too little down pressure is applied to the plow, then it will not cut the ice or compacted snow. However, if too much force is applied, then either the cutting edge may gouge the road surface, causing significant damage often to both the road surface and the plow, or the plow may ride up on the cutting edge so that it is no longer controllable by the operator. Spinning of the truck in such situations is easily accomplished. Further, excessive down force will result in rapid wear of the cutting edge. Given this need for a high level of operator skill, the operation of an underbody plow is a candidate for automation. In order to successfully automate the operation of an underbody plow, a control system must be developed that follows a set of rules that represent appropriate operation of such a plow. These rules have been developed, based upon earlier work in which operational underbody plows were instrumented to determine the loading upon them (both vertical and horizontal) and the angle at which the blade was operating.These rules have been successfully coded into two different computer programs, both using the MatLab® software. In the first program, various load and angle inputs are analyzed to determine when, whether, and how they violate the rules of operation. This program is essentially deterministic in nature. In the second program, the Simulink® package in the MatLab® software system was used to implement these rules using fuzzy logic. Fuzzy logic essentially replaces a fixed and constant rule with one that varies in such a way as to improve operational control. The development of the fuzzy logic in this simulation was achieved simply by using appropriate routines in the computer software, rather than being developed directly. The results of the computer testing and simulation indicate that a fully automated, computer controlled underbody plow is indeed possible. The issue of whether the next steps toward full automation should be taken (and by whom) has also been considered, and the possibility of some sort of joint venture between a Department of Transportation and a vendor has been suggested.

Flame Hardened Snow Plow Blades

Underbody plows and High Speed Ice Blades are an integral part of clearing Iowa roads of snow and ice during winter operations. Changing these blades requires crews to suspend plowing operations and return to the garage decreasing time spent clearing roads and increasing workplace hazards. A blade with a longer lifespan is desired. The Department is determining if using plow blades that have been flame hardened increase longevity of use over the Departments current underbody plow blades that are oven baked. This would reduce downtime and employee exposure to workplace hazards and increase productivity per dollar spent.

Field Measurements of Ice Scraping Loads on Front Mounted Plow Blades, HR-374, 1997

Removal of ice from roads is of the more challenging task in winter highway maintenance. The best mechanical method is to use a truck with underbody plow blade, but such equipment is not available to all agencies charged with winter maintenance operations. While counties and cities often use motor graders to scrape ice, it would be of great benefit if front mounted plows could be used effectively for ice removal. To reveal and understand the factors that influence the performance of these plows, measurement of the forces experienced by the plow blades during ice scraping is desirable. This study explores the possibility of using accelerometers to determine the forces on a front-mounted plow when scraping ice. The plow was modeled by using a dynamic approach. The forces on the plow were to be determined by the measurement of the accelerations of the plow. Field tests were conducted using an "as is" front-mounted plow instrumented with accelerometers. The results of the field tests indicate that in terms of ice removal, the front-mounted plow is not favorable equipment. The major problem in this study is that the front mounted plow was not able to cut ice, and therefore experienced no significant scraping forces. However, the use of accelerometers seems to be promising for analyzing the vibration problems of the front-mounted plow.

Field Measurements of Plow Loads During Ice Removal Operations, HR-334, 1993

One of the more severe winter hazards is ice or compacted snow on roadways. While three methods are typically used to combat ice (salting, sanding and scraping), relatively little effort has been applied to improve methods of scraping ice from roads. In this project, a new test facility has been developed, comprising a truck with an underbody blade, which has been instrumented such that the forces to scrape ice from a pavement can be measured. A test site has been used, which is not accessible to the public, and ice covers have been sprayed onto the pavement and subsequently scraped from it, while the scraping loads have been recorded. Three different cutting edges have been tested for their ice scraping efficiency. Two of the blades are standard (one with a carbide insert, the other without) while the third blade was designed under the SHRP H-204A project. Results from the tests allowed two parameters to be identified. The first is the scraping efficiency which is the ratio of vertical to horizontal force. The lower this ratio, the more efficiently ice is being removed. The second parameter is the scraping effectiveness, which is related (in some as yet unspecified manner) to the horizontal load. The higher the horizontal load, the more ice is being scraped. The ideal case is thus to have as high a horizontal load as possible, combined with the lowest possible vertical load. Results indicate that the SHRP blade removed ice more effectively than the other two blades under equivalent conditions, and furthermore, did so with greater efficiency and thus more control. Furthermore, blade angles close to 0 deg provide for the most efficient scraping for all three blades. The study has shown that field testing of plow blades is possible in controlled situations, and that blades can be evaluated using this system. The system is available for further tests as are deemed appropriate.

Measurement of Ice Scraping Forces on Snow-Plow Underbody Blades, HR-372, 1997

In this study, several new cutting edges for removal of ice from the roadway were tested in a series of closed road tests. These new cutting edges consisted of a variety of serrated shapes. The study also included measurement of ice scraping forces by in-service trucks. These trucks were instrumented in a similar manner as the truck used in the closed-road tests. Results from the closed-road and in-service tests were analyzed by two parameters. The first parameter is the scraping effectiveness, which is defined as the average horizontal force experienced by a cutting edge. The amount of ice scraped from the roadway is directly proportional to the magnitude of the scraping effectiveness. Thus an increase in scraping effectiveness indicates an increase in the amount of ice being scraped from the roadway. The second parameter is force angle, which is defined as tan to the -1 power [vertical force/horizontal force]. A combination of a minimal force angle and a maximized scraping effectiveness represents a case in which the maximal amount of ice is being removed from the pavement without an exceptionally large vertical force. Results indicate that each cutting edge produced a maximal scraping effectiveness with a testing configuration of a 15 deg blade angle and a 23,000 lb. download force. Results also indicate that each cutting edge produced a minimal force angle with a testing configuration of a 15 deg blade angle and a 10,000 lb. download force. Results from the in-service trucks produced similar data and also similar trends within the data when compared to the results of the closed-road tests. This result is most important, as it suggests that the closed-road tests do provide an accurate measure of ice scraping forces for a given blade and configuration of that blade. Thus if the closed-road tests indicate that certain blades perform well, there is now excellent reason to conduct full scale tests of such blades.

Continuous Quality Improvement Snow Plow Accident Study Report, 1995

Identify processes to modify in order to reduce snow plow accidents. Reviewed all [Iowa] D.O.T. snow plow accidents that occurred in calendar years 1992 and 1993.

Evaluation of Virtual Reality Snowplow Simulator Training: A Literature Review, September 2006

Each winter, the Iowa Department of Transportation (Iowa DOT) maintenance operators are primarily responsible for plowing snow off federal and state roads. Drivers typically work long shifts under treacherous conditions. In addition to properly navigating the vehicle, drivers are required to operate several plowing mechanisms simultaneously, such as plow controls and salt sprayers. However, operators have few opportunities during the year to practice and refine their skills. An ideal training program would provide operators with the opportunity to practice these skills under realistic yet safe conditions, as well as provide basic training to novice or less-experienced operators. Recent technological advancements have made driving simulators a desirable training and research tool. This literature review discusses much of the recent research establishing simulator fidelity and espousing its applicability. Additionally, this report provides a summary of behavioral and eye tracking research involving driving simulators. Other research topics include comparisons between novice and expert drivers’ behavioral patterns, methods for avoiding cybersickness in virtual environments, and a synopsis of current personality measures with respect to job performance and driving performance. This literature review coincides with a study designed to examine the effectiveness of virtual reality snowplow simulator training for current maintenance operators, using the TranSim VS III truck and snowplow simulator recently purchased by the Iowa DOT.

Evaluation of Virtual Reality Snowplow Simulator Training, January 2007

Each winter, Iowa Department of Transportation (Iowa DOT) maintenance operators are responsible for plowing snow off federal and state roads in Iowa. Drivers typically work long shifts under treacherous conditions. In addition to properly navigating the vehicle, drivers are required to operate several plowing mechanisms simultaneously, such as plow controls and salt spreaders. There is little opportunity for practicing these skills in real-world situations. A virtual reality training program would provide operators with the opportunity to practice these skills under realistic yet safe conditions, as well as provide basic training to novice or less-experienced operators. In order to provide such training to snowplow operators in Iowa, the Iowa DOT purchased a snowplow simulator. The Iowa DOT commissioned a study through Iowa State University designed to (1) assess the use of this simulator as a training tool and (2) examine personality and other characteristics associated with being an experienced snowplow operator. The results of this study suggest that Iowa DOT operators of all ages and levels of experience enjoyed and seemed to benefit from virtual reality snowplow simulator training. Simulator sickness ratings were relatively low, implying that the simulator is appropriate for training a wide range of Iowa DOT operators. Many reported that simulator training was the most useful aspect of training for them.

Optimal Usage of De-Icing Chemicals when Scraping Ice, November 2003

One of the challenges that faces the winter maintainer is how much chemical to apply to the road under given conditions. Insufficient chemical can lead to the road surface becoming slick, and the road thus becoming unsafe. In all likelihood, additional applications will have to be made, requiring additional effort and use of resources. However, too much chemical can also be bad. While an excess of chemical will ensure (in most circumstances) that a safe road condition is achieved, it may also result in a substantial waste of chemical (with associated costs for this waste) and in ancillary damage to the road itself and to the surrounding environment. Ideally, one should apply what might be termed the “goldilocks” amount of chemical to the road: Not too much, and not too little, but just right. Of course the reality of winter maintenance makes achieving the “goldilocks” application rate somewhat of a fairy tale. In the midst of a severe storm, when conditions are poor and getting worse, the last thing on a plow operator’s mind is a minute adjustment in the amount of chemical being applied to the road. However, there may be considerable benefit and substantial savings to be achieved if chemical applications can be optimized to some degree, so that wastage is minimized without compromising safety. The goal of this study was to begin to develop such information through a series of laboratory studies in which the force needed to scrape ice from concrete blocks was measured, under a variety of chemical application conditions.

Back Warning Sensors for Tow Plows, RB07-012, 2013

Backup warning system devices were evaluated to determine if they would alert winter maintenance snow plow drivers to obstacles directly behind the trailer and out of view of the driver when a unit is backed up. When the sensors on the back of the tow plow were covered with snow during plowing operations, the sensor would go off in the cab and continue going off, which would result in drivers turning the volume of the unit way down. One shop stated that the wireless transmitted signal would be hit or miss depending on the winter weather that they were operating in. The sensors on the back of the tow plow trailer would come in contact with salt brine and in this situation one of the sensors did go bad. The weatherproof box that was designed to keep the system waterproof did not fully keep the moisture out. It was found that the system did alert drivers of items behind the unit and there were no backup accidents reported during the research period.

Visibility and Speed Estimation of Iowa State Highway Commission Snowplows, HR-174, 1975

Many accidents involving Iowa snowplows have happened in recent years. This study investigated the influence of time of day, sex of subject, type of snowplow sign and snowplow speed on the criteria of oncoming driver reaction time and his estimate of snowplow speed. Film strips were made of a car passing a snow-Plow under various experimental conditions. These experimental movie strips were viewed in the laboratory by college student drivers who were asked to indicate their reaction time to slow down and to estimate the speed of the snowplow being passed. The generally best sign condition for the snowplow was to have a striped rear sign and a speed-proportional flashing light in addition to the standard rotating beacon on top of the truck. Several recommendations were made.

Epoxy and Thermoplastic Pavement Markings on US 30 in Carroll County, HR-545, 1995

A one mile section each of thermoplastic and epoxy pavement marking materials were placed on new ACC pavement near Carroll, IA on Highway 30. The markings were evaluated for four years to see if they were suitable materials for durable pavement markings. The epoxy markings were inadvertently repainted after two years. They were performing well up to that time with little plow damage and good retroreflectivity. The thermoplastic dash lines suffered heavy snow plow damage after the first year and were repainted after the third winter. The thermoplastic edge lines performed fairly well for four years.

Local Agency Pavement Marking Plan, TR-551, 2010

The proposed Federal Highway Administration (FHWA) amendments to the Manual of Uniform Traffic Control Devices (MUTCD) will change the way local agencies manage their pavement markings and places a focus on pavement marking quality and management methods. This research effort demonstrates how a pavement marking maintenance method could be developed and used at the local agency level. The report addresses the common problems faced by agencies in achieving good pavement marking quality and provides recommendations specific towards these problems in terms of assessing pavement marking needs, selecting pavement marking materials, contracting out pavement marking services, measuring and monitoring performance, and in developing management tools to visualize pavement marking needs in a GIS format. The research includes five case studies, three counties and two cities, where retroreflectivity was measured over a spring and fall season and then mapped to evaluate pavement marking performance and needs. The research also includes over 35 field demonstrations (installation and monitoring) of both longitudinal and transverse durable markings in a variety of local agency settings all within an intense snow plow state.