Gravel Roads
Road Diets
Highway
FEATURING:
Aurora
Alaska Tribal Technical Assistance Program Center
Newsletter
Rocky Maintenance
12 steps to maintaining unpaved roads
Maintaining Unpaved Roads
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CONTENTS
The basics of maintaining gravel roads
Gravel Road Maintenance
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Zero Roadway Facilities
TABLE
Road reconfiguration guidance
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Like fingerprints, each unpaved road is unique. Wear surfaces may be gravel, crushed rock, sand or clay, but all have one thing in common main- tenance is required to keep the roadways in good driving condition. Traffic displaces material onto shoulders and into ditches, forming ruts in the roadway. Washboarding forms at stop signs, hills, turns and areas of acceleration or braking. Storms, runoff and snow- plowing also take their toll on your unpaved roadways. The following are twelve tips that can help you lengthen road maintenance intervals and avoid rework: 1. To remove wash- boarding, cut the cor- rugations to their full depth, then regrade the area with moist material that will compact. Cor- rugations filled with loose, dry material will reform quickly in areas of high vehicle traffic. Corrugations are best removed by using a scarifier or a serrated cutting edge. 2. Articulating the read frame toward the toe of the moldboard by 2 to 5 degrees helps reduce motor graders’ tendency to bounce, and is extremely effective when cutting out washboards. This places one front tire slightly ahead of the other and allows one tire to be on top of a corrugation while the other is in the bottom. As the tires roll up and down through the washboard, the front axle will pivot up and down keeping the front main- frame stable. Don’t use the crab mode when scarifying wash boarded areas. This can bend the scarifier shanks and/or linkage. 3. To eliminate potholes, cut to the depth of major potholes. Filling holes with loose dry material is ineffective, as traffic quickly displaces the loose material and the holes reform. 4. Typically, begin road maintenance with the moldboard top approxi- mately 2 inches ahead of the cutting edge, and then adjust to the material and conditions. (Continued on page 4)
"Road conditions and your fleet are factors in your agency’s road maintenance"
The Road to zero begins
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Maintaining unpaved roads
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12 Steps
(Continued from page 3) Tip the mold board forward or back to obtain and maintain the desired cutting-rolling action. Tipping the moldboard forward will increase moldboard throat clearance. Generally, a wider throat opening allows better material flow along the mold board in a wide variety of soil types. Maintaining a rolling action on the material while working reduces horsepower required and provides maximum productivity. 5. Material build up into the circle area may increase circle wear. It can also stop material rolling action and cause it to be bulldozed. Bulldozing material requires more horsepower, more traction and reduces motor grader productivity. 6. Apply only enough downward pressure to accomplish the tasks. Excessive downward pressure on a hard, dry surface causes rapid cutting edge war, requires more horsepower and fuel, and reduces productivity. 7. The blade’s tip angle should be positioned with the cutting edge at 90 degrees to the road surface. In this position, downward pressure on the moldboard places less stress on the cutting edge and retaining bolts. The edges also tend to ride over objects, which helps prevent machine damage. 8. For minimum machine stability when maintaining roadways, the motor grader’s main frame should be straight with the drawbar and circle centered under the frame. 9. For the widest possible pass width on the travel surface, keep the moldboard angle as square to the frame as possible. If material starts to flow around the leading end of the moldboard, or the rolling action dies, increase the blade angle. 10. Keep machine travel speed as high as possible for maximum productivity but low enough to prevent machine bounce (generally 4-7 mph). 11. Moldboard angles of 10 to 30 degrees are normally used in light, free-flowing material. Higher moldboard angles of 30 to 50 degrees are required when processing wet-sticky material, mixing large windrows and ditching. 12. To cut hard material or for finishing work, tip the moldboard further forward than the start position. When finishing, tip the moldboard top 4 to 5 inches ahead of the cutting edge so the cutting edge is approximately 90 degrees to the cut surface. This moldboard tip position will generally position the drawbar parallel to the finished grade. As always, road conditions and your fleet are factors in your agency’s road maintenance. Contact the operator training experts at a local dealership to learn more about equipment options available to help you and your operators maintain your unpaved roads in the most efficient manner possible. Resource:Governmental Solutions 2012 Article from Missouri LTAP Newsletter - Summer 2013
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Road Reconfiguration The classic roadway reconfiguration, commonly referred to as a “road diet,” involves converting an undivided four-lane roadway into three lanes made up of two through lanes and a center two-way left-turn lane. The reduction of lanes allows the roadway to be reallocated for other uses such as bike lanes, pedestrian crossing islands, and/or parking. Road diets have multiple safety and operational benefits for vehicles as well as pedestrians, such as: Decreasing vehicle travel lanes for pedestrians to cross, therefore reducing the multiple-threat crash (when one vehicle stops for a pedestrian in a travel lane on a multi-lane road, but the motorist in the next lane does not, resulting in a crash) for pedestrians, Providing room for a pedestrian crossing island, Improving safety for bicyclists when bike lanes are added (such lanes also create a buffer space between pedestrians and vehicles), Providing the opportunity for on-street parking (also a buffer between pedestrians and vehicles), Reducing rear-end and side-swipe crashes, and Improving speed limit compliance and decreasing crash severity when crashes do occur. Background Midblock locations tend to experience higher travel speeds, contributing to increased injury and fatality rates. More than 80 percent of pedestrians hit by vehicles traveling at 40 mph or faster will die, while less than 10 percent will die when hit at 20 mph or less. (Continued on page 6)
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A road diet mostly consists of restriping
There are over 1.6 million miles of unpaved roads (53% of all roads) in the United States. Gravel roads are generally the lowest service provided to the traveling public and are generally inferior to paved roads. Yet, in many rural regions, the volume of traffic is so low that paving and maintaining a paved road is not economically feasible. In many cases, gravel roads exist to provide a means of getting agricultural products in and out of farm fields, timber in and out of forests, or as access to remote areas such as campgrounds and lakes. Many gravel roads serve rural residents as well. Many of these roads will remain unpaved due to very low traffic volume and/or lack of funds to adequately improve the subgrade and base before applying pavement layers. Good gravel road maintenance or rehabilitation depends on two basic principles: proper use of a motorgrader (or other grading device) and use of good surface gravel. The use of the grader to properly shape the road may seem obvious, but the quality and volume of gravel needed is not as well understood. It appears that most gravel maintenance/ rehabilitation problems are blamed on the grader operator when the actual problem is often material related. This is particularly true when dealing with the problem of corrugation or “washboarding”. (Refer to the removable Tech Sheet regarding “Causes and Cures for Washboarding.”) This problem is often perceived as being caused by the grader but is primarily caused by the road material itself. Another important matter to consider is the dramatic change in the vehicles and equipment using low volume roads. Trucks and agricultural equipment are increasing in size and horsepower. The trend is toward even larger machinery. The effect of larger and heavier vehicles on our paved roads is well documented. There is a definite need to build stronger bases and pavements. But the effect on gravel roads is just as serious and often is not recognized. The strength of the subgrade and depth of the material needed to carry today’s heavy loads must be considered. Proper drainage is also important. It has been recognized that very little technical help is available to small agencies that are responsible for managing these roads. Gravel maintenance has traditionally been “more of an art than a science” and very few formal standards exist. As a result, the South Dakota Local Transportation Assistance Program (SD LTAP) along with the help of the Federal Highway Administration (FHWA) developed the Gravel Roads: Maintenance and Design Manual. Ken Skorseth and Ali A. Selim, P.E., of the South Dakota LTAP are the principal authors. The technical advisory committee consists of members from six LTAP centers across the country. The purpose of the manual is to provide clear and helpful information for doing a better job of maintaining gravel roads. It is intended to provide a better understanding of what makes good surface gravel. The manual is designed for the benefit of elected officials, managers, and grader operators who are responsible for maintaining gravel roads. Sections within the manual include: Routine Maintenance & Rehabilitation; Drainage; Surface Gravel; Dust Control & Stabilization; and Innovations. The information provided is as non-technical as possible without sacrificing clear guidelines and instructions on how to do the job right. From Arizona LTAP Newsletter – Spring 2004
When appropriately applied, road diets have generated benefits to users of all modes of transportation, including bicyclists, pedestrians, and motorists. The resulting benefits include reduced vehicle speeds, improved mobility and access, reduced collisions and injuries, and improved livability and quality of life. When modified from four travel lanes to two travel lanes with a two-way left-turn lane, roadways have experienced a 29 percent reduction in all roadway crashes. The benefits to pedestrians include reduced crossing distance and fewer midblock crossing locations, which account for more than 70 percent of pedestrian fatalities. Guidance Road diets can be low-cost if planned in conjunction with reconstruction or simple overlay projects, since a road diet mostly consists of restriping. Roadways with Average Daily Traffic (ADT) of 20,000 or less may be good candidates for a road diet and should be evaluated for feasibility. It has been shown that roads with 15,000 ADT or less had very good results in the areas of safety, operations, and livability. Driveway density, transit routes, the number and design of intersections along the corridor, as well as operational characteristics are some considerations to be evaluated before deciding to implement a road diet. It is a good practice for someone in an agency to know well in advance of when road reconstruction and overlay projects will be initiated so an evaluation can be conducted. It is important to analyze and understand the effects of the proposed change, obtain input from the community stakeholders, and ensure the appropriate elements are included in the project. Improvements to intersection turn lanes, signing, pavement markings, traffic control devices, transit stops, and pedestrian and bicyclist facilities may be needed to support this concept. It should be noted that the classic four-to-three-lane road diet is very compatible with single-lane roundabouts. Article from California LTAP Newsletter – Summer 2013
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The Interstate system ceremonially begins at Zero Milestone, a small and often overlooked obelisk next to the National Christmas Tree on the Ellipse south of the White House. It is the point from which a historic Army convoy led by Lt. Col. Dwight Eisenhower began in 1919, making clear our nation’s need for a system of highways and byways. Now, we are at a new milestone. We are embarking on a similarly ambitious quest, and we need you to come with us. We call it the “Road To Zero.” This means zero roadway fatalities. Absolutely zero. Last year in America, 35,092 people died on our nation’s roads – a 7.2 percent increase over the previous year, and one of the biggest single-year increases on record. The numbers tend to numb us, by making us think of these victims as simple statistics. In reality, each one of them was a person – someone’s son, daughter, parent, co-worker, neighbor, friend, or loved one. Each of these people was on a journey, whether in a car, truck, motorcycle, bus, bike or on foot – and failed to reach their destination safely. There are many possible reasons. It could have been the result of distracted driving or driving under the influence of alcohol. Bad weather may have played a part. Perhaps the road they used was heavy with traffic, or in need of repair. Whatever the case, highway safety requires relentless vigilance from all of us – both as road users and as pedestrians – and the open-mindedness to look for better tools and methods that can help us reach one of our most elusive goals: zero deaths on our roads. This is why Secretary Foxx, NHTSA, FHWA, FMCSA and many others in the transportation community are joining forces. This “Road To Zero Coalition” is increasing its efforts and enlisting the support of one of the nation’s most influential safety groups – the National Safety Council – to help us get to zero. Our “Road To Zero” is more than a slogan. It’s a mission that transportation authorities in the U.S. and abroad have made their number one priority. While zero deaths is an ambitious goal, it is the only acceptable one. It’s a goal that will take time to reach, and it will require significant effort from everyone – including the public – but we are prepared to do whatever it takes to succeed. As Steve Jobs once said, “good enough is never good enough.” Working together, we can reach a day when there are no fatalities on the nation's roadways, sidewalks and bicycle paths. Today is the day we work to stem the tide of roadway tragedies. As we embark on the “Road To Zero,” today is a Zero Milestone of a different kind – and we are counting on you to join us. Posted by NHTSA Administrator Mark Rosekind, Ph.D.; FHWA Deputy Administrator David Kim; and FMCSA Administrator T.F. Scott Darling, III.
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Up Coming Conferences
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New Permafrost Map Shows Regions Vulnerable to Thaw, Carbon Release
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Jan 8-12 96th Annual Meeting - Transportation Research Board Feb 10-14 ATSAA Annual Convention and Traffic Expo Apr 9-13 National Association of County Engineers
Oct 18-20 Accounting for Transportation Oct 18-20 Grant Writing - Proposal Writing for Tribal Personnel Dec 13-15 Planning 101
Calendar of Events
Jan 18-20 Accounting for Transportation - 2nd Offering Jan 30-Feb 3 Spring Tribal Transportation Institute Feb 21-23 Accounting for Transportation - 3rd Offering Apr 4-6 Accounting for Transportation - 4th Offering
TRAINING 2017
EVENTS 2016
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A new mapping project has identified regions worldwide that are most susceptible to dramatic permafrost thaw formations, known as thermokarst, and the resulting release of greenhouse gases. University of Alaska Fairbanks researchers David McGuire and Vladimir Romanovsky were part of the project, which was led by University of Alberta researcher David Olefeldt. They found that about 20 percent of the globe’s northern permafrost region is potential thermokarst landscape. The research can be used in infrastructure and ecosystem planning and greenhouse gas modeling. The journal Nature Communications published the study this week. Northern permafrost soils store twice as much carbon as is currently in the atmosphere. When permafrost thaws, the organic matter in the previously frozen soil begins to decay, releasing greenhouse gases like carbon dioxide and methane. Those gases can contribute to climate warming and further permafrost thaw. “The most dramatic changes are likely to occur where permafrost thaw is accompanied by land surface collapse, known as thermokarst,” Olefeldt said. Scientists can use the new map to test assumptions about how fast the soil organic matter will turn into greenhouse gases in these areas. Thermokarst occurs when thawing soil contains large amounts of ice. When that soil and ice thaws, the water drains away, leaving a void that can lead to more than two dozen distinct collapse landforms, including gullies, slumps, wetlands and lakes. Each type affects greenhouse gas emissions in its own way, and up until now no one has been able to account for all of them at the global scale. “There haven’t been good estimates on how thermokarst disturbance could affect the release of carbon out of the soil,” said McGuire, who is part of the Alaska Cooperative Fish and Wildlife Research Unit at the UAF Institute of Arctic Biology and U.S. Geological Survey. Scientists have been hindered by both the diversity of the thermokarst landforms and a lack of information on where these thermokarst landforms are most likely to occur in a warming world. “This map is a first step to answer how the landscape will change with the thawing of permafrost in a warming climate. This is the big picture, it is useful as a general idea of what we should expect on a circumpolar scale,” said Romanovsky, a researcher at the UAF Geophysical Institute. One of the most important results of the project was developing a method to prepare a map that will help scientists and resource managers estimate the effects of a warming climate on permafrost in these regions, Romanovsky said. “In Alaska we can see that some areas will be more vulnerable than others. For example, you can see from the map that the Yukon Delta and the North Slope regions will probably undergo significant landscape changes.” The thermokarst landscape map is available to anyone through the online site hosted by the U.S. Department of Energy’s Oakridge National Laboratory in Tennessee. Article from UAF Marmian Grimes
TRAINING 2016
Oct 8-14 NCAI 73rd Annual Convention & Marketplace Oct 20-22 AFN Convention (Fairbanks) Oct 31 Environmentally Sustainable Construction Practices in Cold Regions Nov 13-15 2016 State Planning Conference Nov 15-17 Tribal Government Symposium Nov 29-Dec 2 Tribal Providers Conference
EVENTS 2017
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