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Converting Paved Roads to Unpaved (2015)

Chapter: Appendix D - Case Examples

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Suggested Citation:"Appendix D - Case Examples ." National Academies of Sciences, Engineering, and Medicine. 2015. Converting Paved Roads to Unpaved. Washington, DC: The National Academies Press. doi: 10.17226/21935.
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Suggested Citation:"Appendix D - Case Examples ." National Academies of Sciences, Engineering, and Medicine. 2015. Converting Paved Roads to Unpaved. Washington, DC: The National Academies Press. doi: 10.17226/21935.
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Suggested Citation:"Appendix D - Case Examples ." National Academies of Sciences, Engineering, and Medicine. 2015. Converting Paved Roads to Unpaved. Washington, DC: The National Academies Press. doi: 10.17226/21935.
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Suggested Citation:"Appendix D - Case Examples ." National Academies of Sciences, Engineering, and Medicine. 2015. Converting Paved Roads to Unpaved. Washington, DC: The National Academies Press. doi: 10.17226/21935.
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Suggested Citation:"Appendix D - Case Examples ." National Academies of Sciences, Engineering, and Medicine. 2015. Converting Paved Roads to Unpaved. Washington, DC: The National Academies Press. doi: 10.17226/21935.
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Suggested Citation:"Appendix D - Case Examples ." National Academies of Sciences, Engineering, and Medicine. 2015. Converting Paved Roads to Unpaved. Washington, DC: The National Academies Press. doi: 10.17226/21935.
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Suggested Citation:"Appendix D - Case Examples ." National Academies of Sciences, Engineering, and Medicine. 2015. Converting Paved Roads to Unpaved. Washington, DC: The National Academies Press. doi: 10.17226/21935.
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Suggested Citation:"Appendix D - Case Examples ." National Academies of Sciences, Engineering, and Medicine. 2015. Converting Paved Roads to Unpaved. Washington, DC: The National Academies Press. doi: 10.17226/21935.
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66 This section provides case examples from 15 states in the United States and one Canadian province for which transporta- tion agencies have converted paved roads to unpaved. The case examples were developed using information gained from the survey, follow-up interviews, and the literature. ALABAMA In Franklin County, Alabama, 20 mi of very poor condition road were converted to unpaved. The road was converted using a full-depth reclaimer and consists of a red clay and gravel mixture and the recycled old surfacing. A thin layer of crusher run (crushed limestone) was hauled in to supplement the exist- ing materials creating a white overlay that differentiates this road from the other red dirt roads in the county, thus “softening the blow” of the transition from paved to unpaved. The road has an average daily traffic (ADT) of 21 to 50 vehicles and was converted within the last year (2014). The road was changed to an unpaved surface because of the costs of maintaining the road, complaints from the public, and safety concerns, but the lack of revenue was the primary cause for the road conversion. They would have preferred to keep patching the road but did not have the funds to support this. The converted road is per- forming well, the county has saved money by doing the con- version, and there has been no documented increase in vehicle crashes. Public reaction has been both positive and negative. Outreach efforts included contacting the local media outlets and one-on-one meetings with road residents and legislators, which were deemed somewhat successful. There has been some pressure to repave. Franklin County is unique because it uses a robust geo- graphic information system (GIS) tool that is incorporated into the asset and pavement management systems. They use these tools to model their road system, prioritize their needs, and make informed management decisions. They can easily enter data into the system, which they can adjust and supplement with additional information to fit their needs. The software allows for consideration of surface condition, base condition, traffic volumes, number of residents, segment classification, repair costs, and other factors when rating a road. They inspect each road in the county every 2 years and enter the new data into the GIS system. A rating from 1 to 100 is given to each road for the surface and base condition. The system then uses a combination of the rating, road classification, ADT, and a few other factors to prioritize roads for maintenance and repaving. The system then suggests the level of service warranted for the road—for example, paved, gravel, or chip sealed surface—and provides a relative ranking for each road that helps the county determine where to spend money and the level of maintenance required. All of this information helps with budgeting. They also have a database of unit prices for a variety of materials and processes, by which they can check boxes on a computer screen for various maintenance and construction procedures and the system will provide a budget based on these selections. One aspect of the system the county really likes is that it is easy to make and change maps, which are great tools for communi- cating with the public. The maps can show roads as red if they are in bad condition and green if they are in good condition. They have found these color codes better convey the real- ity of the road network condition than do pages of budgets and condition data. Ultimately this system is an integral part of what they do Franklin County, and is a great tool for making strategic decisions. CALIFORNIA A total of 6 mi of road converted from paved to unpaved in Napa County (4 mi) and Yolo County (2 mi), California, and are discussed here. In Napa County, the 4 mi of road converted was a connector road with ADT of 150 to 200 vehicles. The original pavement was asphalt concrete in poor condition. The old surface material was recycled into the new road sur- face using a contracted pulverizer, and gravel was trucked in to supplement the existing materials. The road surface was stabilized using an enzymatic soil stabilizer that was mixed into the water in a truck that was attached to the pulverizer; the stabilizer was then incorporated into the surface layer. They feel this method utilizing the enzyme made for a better driving surface. The road is graded about once a year; in addition, clay has been added to a coarse rocky section to get a better soil mix, and water has been added to reactivate the enzyme stabilizer. The road was converted more than 5 years ago because the cost of maintaining the road was unsustainable. Public reaction to this road conversion project was negative. A public hearing was held, with mixed results in terms of success. There was pressure to repave, and this may be due in part to homeowners being told the road would be repaved in a couple of years. At one point in time, complaints on the newly converted road were coming from a federal agency on behalf of a constituent. In Yolo County, California, 2 mi of road with ADT of 21 to 50 vehicles were converted from a poor condition pavement to an unpaved road surface more than 5 years ago (prior to 2010). The old pavement surface was recycled and incor- porated in the new surface, gravel was hauled in to supple- ment the existing materials, and the surface was stabilized with an enzyme product incorporated into the surface layer. The road was converted because of high maintenance costs, complaints from the public, and safety concerns. At this time APPENDIX D Case Examples

67 the converted road is performing well, the county has saved money, the road has required less maintenance than antici- pated, and there has been no documented increase in vehicle crashes. The county does have plans to convert more roads from paved to unpaved. The county worked with outside par- ties to determine the proper methods to be used to convert the road. No public outreach efforts have been made, and there has been no pressure to repave. IOWA In this section, 50 mi of road converted from paved to unpaved in three Iowa counties are reviewed. In Decatur County, Iowa, 41 mi consisting of asphalt con- crete in fair condition, pavement with a surface treatment in poor condition, a combination of pavements in fair condition, and portland cement concrete pavement in fair condition were converted to unpaved. The old surfaces were recycled, and new gravel was hauled in to supplement the existing materi- als. At this time they have converted only roads with chip seal surface treatment back to gravel. Documents used to provide guidance in the road conversion project included the AASHTO Guidelines for Geometric Design of Very Low-Volume Local Roads (the Green Book), the Very Low Volume Roads Guide, which was used to establish the finished section, and commu- nications with other engineers discussing the trials and errors of what methods provided the best finished surface. ADT on the road segments ranges from 100 to 150 vehicles, and the reason for the conversion was the cost of maintaining the roads. The road were converted 1 to 2 years ago (2013–2014), and at this time the road is performing well and there has been no documented increase in vehicle crashes. Public reaction to the road conversion has been both positive and negative, with some of the public happy that they now have a uniform driving surface, whereas others are unhappy the road is no longer a paved and dust-free surface. There has been pressure from the public to repave the road. In this county they do not have the funding to pave new miles of hard-surfaced roads, even with a new fuel tax increase. In Jefferson County, Iowa, 6 mi of pavement with a sur- face treatment in poor condition were converted to an unpaved road. The original pavement was recycled and mixed with gravel that was hauled in to supplement the existing material, followed by the application of a chemical stabilizer or dust suppressant that was incorporated into the surface layer. Jef- ferson County relied on the experience of others who have conducted road conversion projects to aid in their conversions. The road, with an ADT of 300 to 500 vehicles, was converted 2 to 3 years ago (2011–2013) because of the cost to maintain the road. At this time the road is performing well, has required less maintenance than anticipated, and the county has saved money. Public sentiment to the road conversion was negative, and there has been pressure to repave. The county has plans to convert more roads from paved to unpaved in the future. In Washington County, Iowa, 3 mi of paved road with a seal coat surface treatment in poor condition and an ADT of 21 to 50 vehicles were converted to unpaved more than 5 years ago (prior to 2010). The old road was recycled using a motor grader, and gravel was hauled in to supplement the existing materials to create the new unpaved road surface. The road was converted because of the cost of maintaining the road. The county determined it was more economical to maintain the road as unpaved. At this time the road is per- forming well, has saved the agency money, and has required less maintenance than anticipated. Outreach efforts included talking with stakeholders, explaining why the county was converting the road and the high cost to maintain the current surface compared to a new unpaved surface. There has been no pressure to repave the road, but high average daily vehicle counts may require repaving of the road. The converted road has had issues with gravel loss because of varying transporta- tion modes (e.g., Amish horse-drawn buggies); for this reason they will be testing a road stabilizer (summer 2015). They also had some issues with breaking up the chunks of seal coat, which caused issues with the driving surface and lack of uniformity. KANSAS In Montgomery and Stafford Counties in Kansas, about 45 mi of road have been converted from paved to unpaved. In Stafford County, 42 mi of road were converted with an ADT of 21 to 50 vehicles. The original asphalt surface treatment was in poor condition. Recycling machines were used to grind up, recycle, and incorporate the old surface into the new unpaved surface. A clay mix was used to cap the gravel road and aided in pro- viding a smoother driving surface. The road has an extremely sandy soil type that is unstable, so the clay functioned as a stabilizer. The reasons for converting the road were the cost to maintain the road and safety concerns. Input from supervisors was used to complete the conversion, and the road conversion took place 5 or more years ago (prior to 2010). The converted road is not performing well. They have spent more money than anticipated, the road has required more maintenance than anticipated, and the overall reaction to the conversion has been negative. In addition to this, there has been pressure to repave the road. Consequently, a 2-mi section of the converted road was repaved with asphalt because of high truck volume. In Montgomery County, Kansas, 4 mi of road were con- verted from paved to unpaved in the 1980s. The original pavement consisted of a mix of asphalt concrete in good con- dition, an asphalt surface treatment in good condition, and a combination of pavements types in good condition. The orig- inal pavement surface was recycled and incorporated into the new unpaved surface. The rationale for the conversion was the high cost to maintain the road and low ADT, from 51 to 100 vehicles. Input on how to convert the road was provided by the commissioners at the time. At this juncture, the road is not performing well, public reaction to the road conversion

68 has been negative, and there has been pressure to repave. This may be in part because homeowners were told the road would be reasphalted a couple years after it was converted to unpaved, and this has not occurred. MICHIGAN In Montcalm County, Michigan, 15 mi of road surfaced with asphalt concrete in poor condition or pavement with a surface treatment in poor condition were converted to unpaved. New gravel was hauled in to supplement the existing materials, and then the old surfacing was recycled and mixed with the new gravel to better incorporate both into the road surface. A surface application of a dust suppressant was applied at 4,000 gal per mi of 26% calcium chloride every 21 to 28 days (from mid- May to mid-September) at a chloride cost of $550.00 per mile. Application rates and frequency of application varied based on moisture and ADT. The road was converted because of the cost to maintain the road, complaints from the public, and safety concerns. Ultimately the decision to convert the road was based on the cost history of the road, accident reports, and estimated future funding levels. ADT for this road is 500 to 1,000 vehicles. The road conversion occurred over a 6-year period, with 2 to 3 mi converted each year. By converting the road, the county has saved money and there has been no documented increase in vehicle crashes, but the public reaction to the road conversion was negative, and the converted road has required more maintenance than anticipated. Additionally, there has been pressure to repave the road. The county did conduct outreach efforts, but no details were provided. The county does plan to convert more roads from paved to unpaved. MINNESOTA In this section, three counties in the state of Minnesota that have converted about 22 mi of road from paved to unpaved are discussed. In Freeborn County, Minnesota, 0.2 mi of asphalt concrete road in poor condition, with an ADT of 300 to 500 vehicles, were converted to an unpaved road 2 to 3 years ago (2010–2013). The road segment has the unique issue of a subgrade consisting of peat bog with a flowing artesian spring. The conversion pro- cess consisted of recycling the old pavement surface and hauling in and placing Class 2 limestone over Class 5 aggregate base. Magnesium chloride surface stabilization was incorporated into part of the surface layer. The road was converted because of the cost of maintaining the road, complaints from the public, and safety concerns. The decision to convert this road seg- ment came from an aggregate prioritization plan. At this time, the converted road segment is performing well, has saved the agency money, has required less maintenance than anticipated, and there has been no documented increase in vehicles crashes. Public reaction to the road conversion has been negative, and there has been pressure to repave the converted road segment. Failure of the road has occurred in the springtime as the road thawed, and the county does not plan on doing a conversion this same way again. The county is currently working with elected officials to help educate the road users. Freeborn County has developed a method to assess all of the miles of gravel surfaced roads, which entails coring three points per miles in a zig-zag pattern to determine aver- age aggregate thickness, setting targets based on ADT and presumed heavy commercial ADT, and prioritizing for addi- tional aggregate base and then aggregate surfacing (Class 2 and magnesium chloride) if ADT is less than 100 vehicles. Freeborn County also began working with aggregate pro- ducers on the quality of the aggregates and to alter the state specifications to find a better surface versus base aggregate. In Jackson County, Minnesota, 1 mi of asphalt concrete in poor condition with an ADT of 51 to 100 vehicles was converted to an unpaved road within the last year (2014). The original pavement was recycled and incorporated into the new unpaved road surface. The road was converted because of the cost to maintain the road, as well as the diminished importance of the road owing to the reconstruction of another thoroughfare serving the community. At this time, the road is performing well and has saved the county money. Outreach efforts prior to the conversion included educating the County Board and City Council on the process, educating them on why converting the road was necessary, and involving them in the conversion. The county found that long-term planning and discussion with the County Board and City Council worked well. The road conversion took place more than 10 years after initial discussions began. The county has plans to convert more roads from paved to unpaved in the future. In St. Louis County, Minnesota, 20 mi of asphalt concrete in poor condition were converted to an unpaved road 1 to 2 years ago (2012–2014). The original surface was recycled, new gravel was hauled in to supplement the existing material, and a chemical stabilizer was incorporated into part of the sur- face layer. For this road, the ADT (51 to 100 vehicles) was too low to warrant bituminous surface treatment—instead they decided on full-depth reclamation with a stabilized base to increase strength. The road was converted because of the cost of maintaining the road and safety concerns coupled with complaints from the public. At this time the road is perform- ing well, has required less maintenance than anticipated, has saved the county money, and there has been no documented increase in vehicle crashes on the converted road. However, there has been pressure to repave the converted road. For this conversion project, timing did not allow for outreach, but they would conduct public outreach going forward with future road conversion projects. The county has plans to convert more roads in the future.

69 MONTANA In Musselshell County, Montana, two road conversions of more than 5 mi occurred. The first conversion was on road with less than 20 ADT; the road had a surface constructed of a combination of materials and was in poor condition. The new unpaved surface had a road surface stabilizer incorpo- rated into part of the surface layer. The road was converted because of costs associated with maintaining the road and because some sections were deteriorated beyond repair. The second road conversion project in Musselshell County, Mon- tana, involved the conversion of 3 mi of paved road constructed from a combination of materials that was in good to poor condition. ADT on this road is 51 to 100 vehicles. The new, unpaved road consists of millings (reclaimed asphalt from other roads) laid out over gravel with a road surface stabilizer incorporated into part of the surface layer. The conversion occurred because of the cost to maintain the road and the high cost of chip sealing. For both conversions in Musselshell County, the original pavement surface was recycled and incorporated into the unpaved surface. Both road conversion projects occurred 2 to 3 years ago (2010–2013), and the roads are performing well. Converting the roads from paved to unpaved has saved the county money, and subsequently they have plans to con- vert more roads. The reaction from the public regarding the road conversion was both positive and negative, with some residents complaining about the dust. For these conversions, the county determined it was better to have a recycled sur- face that can be kept smooth using a motor grader than a road full of potholes and other hazards. At this point in time there has been no pressure to repave. NEBRASKA In this section, two counties in the state of Nebraska that have converted about 25 mi of road from paved to unpaved are discussed. In Arthur County, 5 mi of local farm-to-market road with an ADT of 51 to 100 vehicles were converted from paved to unpaved. The original pavement surface was asphalt cement in poor condition, and to fix the existing road would have required a full rehabilitation. The road was recycled in place with a rented pulverizer, and aggregate was added to supplement the existing materials. The recycled asphalt served as a stabilizer, and no additional surface treatment was required. The road was converted because of costs to maintain the road and a lack of available federal funds for rehabilitation. The road conversion occurred 5 or more years ago (prior to 2010), and at this time the road is performing well, has saved the county money, and there has been no documented increase in vehicle crashes. Public outreach efforts consisted of a public hearing and were deemed to be successful. There has been no pressure to repave the road, and currently this is the best gravel road they have in the county. In Sheridan County, Nebraska, 15 mi of paved road with an original pavement type of asphalt concrete were converted to unpaved. To construct the new road surface, gravel was hauled in to supplement existing materials, and a stabilizer was incorporated into the surface layer of the unpaved road. The road was converted because of safety concerns and the cost of asphalt versus the cost of gravel. The road was con- verted 2 to 3 years ago (2010–2013), and at this time the road is performing well, has saved the county money, and there has been no documented increase in vehicle crashes, but the road has required more maintenance than anticipated. Public reac- tion to the road conversion has been negative, and there has been some pressure to repave. Outreach efforts to the public included meeting with road district patrons and explaining the associated costs to them. The county says they would perform the conversion again. NORTH DAKOTA In this section, two counties in the state of North Dakota that have converted about 40 mi of road from paved to unpaved are discussed. In Cass County, North Dakota, 5 mi of road were converted from asphalt concrete in poor condition to an unpaved road. The old surface was recycled and mixed with gravel that was hauled in to supplement the existing materials, followed by application of a road surface stabilizer that was incorporated into part of the surface layer. The road was converted because of the cost to maintain the road, as well as safety concerns. The decision to convert the road was made using a cost analysis tool called the Surface Selection Tool that was developed by the Upper Great Plains Transportation Institute. They are cur- rently developing a web-based surface selection tool, which will use life-cycle costs to determine which surface treatments are most cost-effective for various ADTs (additional informa- tion on this document can be found in chapter four, Resources and Available Documents). The road was converted 1 to 2 years ago (2013–2014) and is performing well. The conver- sion has saved the county money, and no documented increase in vehicle crashes has occurred. Public outreach consisted of a public meeting in which they were able to correct some mis- conceptions about converting roads from paved to unpaved, and there has been no pressure to repave the road. In Ramsey County, North Dakota, 35 mi of farm-to-market road with an ADT of 21 to 50 vehicles were converted from asphalt concrete in poor condition to an unpaved road more than 5 years ago (prior to 2010). The original pavement sur- face was recycled with an asphalt recycling machine, and new gravel was hauled in to supplement the existing materials. Dust suppressant has been applied in front of residences along the route at a minimal cost share to the residents. The road was converted because of cost to maintain the road, complaints from the public, and safety concerns. Outreach included pub- lic meetings to explain that the costs of maintaining the road as asphalt were prohibitive and radio interviews. Both efforts

70 were deemed successful. The county explained what their intentions were for the road conversion project and handed out sheets with projected costs to repair the road and main- tain as asphalt. The county acknowledges that they should have worked with residents living on the route more. As a side note, the county asked the voters to add $10 million to road maintenance funds at around the time the conversion was occurring; the vote was passed. At this time the road is performing well, has saved the county money, has required less maintenance than anticipated, and there has been no docu- mented increase in vehicle crashes. Road users had a negative reaction to the road conversion the first couple of years after it was converted, but once they got used to gravel road condi- tions they were positive about the conversion because the road is now safer. There has been no pressure to repave. OHIO In Coshocton County, Ohio, 30 mi of road were converted from paved to unpaved. The original asphalt concrete was in poor condition, and the roads were converted because of the cost of maintenance and safety concerns. Although no documents were available for use in the conversion process, engineering principles and economics analysis were used. The ADT on the converted roads is 200 to 300 vehicles. A second road conversion project in the county involved the conversion of 3 mi of asphalt concrete roadway in poor condition into an unpaved road surface. This conversion took place because of safety concerns. For both road conversions, they used a road grader and dump truck to place gravel on top of the deteriorating roads, to supplement the existing material, making the conversion somewhere between active and passive conversion. They do not typically use a dust suppressant or stabilizers, with the exception of occasionally using brine from oil and gas opera- tions that is sprayed on the road as a means of disposal. Addi- tionally, both road conversions took place 5 or more years ago (prior to 2010). The reaction to the conversions was negative, but the county still has plans to the convert more roads from paved to unpaved in the future. No outreach efforts were made for either conversion, and there has been pressure to repave, with specific complaints about dust. In this county the pub- lic felt like converting roads from paved to unpaved was los- ing ground and had trouble understanding why there was not enough money for repaving. If funds permit, they will try full- depth reclamation to improve the unpaved roads. OREGON In the Malheur and Siuslaw National Forests in Oregon, 25 lane-miles of road have been converted from paved to unpaved. The ADT for the road conversion that occurred in Malheur National Forest was less than 20 vehicles along the 5-mi stretch of road. The original pavement type was asphalt concrete in poor condition. The paved surface was recycled in place using an asphalt pulverizer, which was adjusted to reclaim down to 1.5 ft, essentially digging out the road and laying it back down, followed by compaction three times with a roller. Four inches of crushed rock/gravel were then added as a cap, and the surface was treated with a road surface stabiliza- tion product that was incorporated into the surface layer. Prior to the road conversion, they consulted with geotechnical engi- neers. Plans were made to address any base issues that arose, and consequently they ended up replacing a couple of failed culverts. The road was converted 2 to 3 years ago (2010–2013) because of the cost to maintain the road and safety concerns. The converted road is performing well, has saved the agency money, requires less maintenance than anticipated, and there has been no documented increase in vehicle crashes. The agency has plans to convert more roads from paved to unpaved. Out- reach efforts included project scoping, which was deemed suc- cessful, and there has been no pressure to repave. This was an old timber harvest road that was used again for timber harvest- ing immediately after the conversion, so increased traffic and compaction occurred, and the road has held up well. The second road conversion project occurred in Siuslaw National Forest more than 5 years ago (prior to 2010) and involved 20 mi of road with an ADT of 51 to 100 vehicles. The original surface had a bituminous surface treatment chip seal surfacing that was unsafe. The old surface was recycled into the surface layer of the unpaved road. The road conversion occurred because of the cost of maintaining the road and safety concerns. The converted road surface is performing well, has saved the agency money, and there has been no documented increase in vehicle crashes. Overall reaction has been positive, and the forest has plans to convert more roads. No public out- reach efforts were used, and there has been pressure to repave. PENNSYLVANIA The Pennsylvania Bureau of Forestry, in conjunction with Pennsylvania’s Center Dirt and Gravel Road Maintenance Program, performed a demonstration project on a portion of Linn Run Road located in Linn Run State Park in Westmore- land County. Initially, the work plan proposed using full- depth reclamation to break up the asphalt and mix it with the existing base material to a depth between 6 and 8 in. Water and chemical stabilizers would then be added to achieve optimum moisture content, followed by crowning and road shaping performed by a road grader and compacted using a roller. Drainage issues were addressed in the work plan, with numerous underdrains wrapped with permeable geotextile and ditching to prevent water movement across the top of the road surface (Shearer and Scheetz 2011). Upon installation of the first drainage element, large boul- ders beneath the 1 to 2 in. of asphalt overlay were discovered and prevented the use of the full-depth reclamation process because of machinery limitations. The large boulders were

71 used in the original construction of the road as a base to cover an impermeable clay layer found during excavation for the drain- age system. The work plan was updated, and the asphalt was crushed with a crawler tractor fitted with a ripper and mixed with the minimum amount of aggregate to prevent the asphalt from rebinding. A geotextile was placed on top of the reclaimed base and then covered with 6 in. of driving surface aggregate applied using a paver. The geotextile was chosen because it allows for the flow of water through the layer but prevents the downward migration of fine soil particles that could clog the underdrain system in addition to providing stabilization and even load distribution. The aggregate was delivered to the site at optimum moisture content and compacted with rollers (Shearer and Scheetz 2011). The final product of the reclaimed road was a hard-wearing surface that required less maintenance and lost less sediment to runoff than does a traditional gravel road. Despite the com- plications from the large boulders in the original road base, the project budget did not exceed the initial value of $100,000. Proper site investigation was cited as one reason for the suc- cess of the project, primarily the installation of a drainage sys- tem to route water off of and away from the road surface. If initial core samples and other evaluations were not performed, proper preparation of the road base could not have been com- pleted prior to the recycling of the asphalt road surface. This could have led to issues with the road stability and increased maintenance costs because of poor construction (Shearer and Scheetz 2011). SOUTH DAKOTA In this section, four counties in the state of South Dakota that have converted more than 100 mi of road from paved to unpaved are discussed. In Brookings, South Dakota, two road conversion proj- ects were conducted. The first road conversion to be discussed involved 20 mi of asphalt concrete that was converted to an unpaved road surface. The road was converted because the low ADT on the road (100 to 150 vehicles) did not justify reconstructing the pavement in a life-cycle cost analysis. Infor- mation available included a Transportation Learning Network video conference titled Alternatives to Paving. In addition to this, in-house knowledge of existing base depth materials and the material quality, recycling, base construction, priming, and seal coating were used. The public initially objected to the con- verted road but was then happy after getting a good gravel sur- face to drive on. The second road conversion involved 2 mi of asphalt concrete converted to an unpaved road with an asphalt emulsion surface. Additionally, they used a modified surface gravel specification to get a better bound surface to reduce blade maintenance and loose aggregate on the surface (which brings complaints). The road was recycled, reshaped, recom- pacted, and a chip seal was placed on the surface. A half-gallon per square yard of AE200 emulsion asphalt was injected and mixed into the upper 3 in. of the recycled layer to strengthen the recycled base. ADT on this road was 300 to 500 vehicles, but the cost of maintaining and the cost of total reconstruction to pavement were prohibitive. For these reasons, a seal coat was determined to be adequate. Following the conversion, the pub- lic was happy and did not even know the road was not repaved. Both road conversions were completed 2 to 3 years ago (2010–2013), and the roads are performing well. By perform- ing the road conversions, the road agency has saved money, there has been no documented increase in vehicle crashes on the converted roads, and the converted roads have required less maintenance than anticipated. At this time there are plans to convert more roads from paved to unpaved, in part because of the experience gained in the process and increased confidence in the process. Outreach efforts included public meetings and informal contact with residents. The agencies found presenting good cost and budget data to justify the decision to convert the roads helped in public understanding but noted that trying to convey technical data can be confusing to the public. Public reaction to the road conversions has been positive, and there has been no pressure to repave the roads. In Brown County, South Dakota, 40 mi of asphalt concrete pavement (in good condition) with a chip seal surface treatment (in fair condition), and a combination of pavements including portland cement (in fair condition) were converted to unpaved. A second road conversion project in Brown County involved 30 mi of asphalt concrete pavement (in poor condition), with a chip seal surface treatment (in poor condition), and a combina- tion of pavement types (in poor condition) being converted to unpaved road segments. For both road conversion projects in Brown County, the unpaved road surface was made using recycled materials from the original paved surface, and new gravel was hauled in to supplement the existing materials, fol- lowed by application of dust suppressant. Brown County has used different recycling equipment (mills) and has purchased a loader-mounted reclaimer they use for projects of less than 0.5 mi. (The larger reclaimers are faster and more efficient for longer road sections.) Brown County runs a padfoot roller (sheepsfoot) behind the mill to help break down the chunks and aid in compaction. In 2015, Brown County experimented with a soybean- derived base and surface stabilizer and has used cement as a base stabilizer in the past on roads that will be repaved but avoids this on reclaimed roads that remain unpaved because of the potential for pothole formation. For both road conver- sion projects, the road segments were converted because of the cost of maintaining them. Both roads have an ADT of 21 to 50 vehicles, and the road conversions took place 5 or more years ago (prior to 2010). Information used to convert the road was found in documents on the Internet and gleaned from talking with industry representatives. At this time the roads are performing well, have saved the county money, and there has been no documented increase in vehicle crashes on the converted road segments. Outreach efforts by the county consisted of town meetings and public discussions that were

72 deemed somewhat successful. Public reaction to the road con- version has been overall positive; the road users like it, but the residents living adjacent to the roads do not like it. The county has plans to convert more roads from paved to unpaved in the future. The next time they convert a road, they will likely col- lect cores to make sure they have the correct quantity of gravel for a proper mix of gravel to asphalt after reclaiming. In Kingsbury County, South Dakota, 16 mi of asphalt con- crete in fair condition and pavement with a surface treatment in poor condition were converted to an unpaved road 2 to 3 years ago (2010–2013). The original pavement surface was recycled with new gravel hauled in to supplement the existing materi- als. The recycled material and gravel mix was watered and rolled while being placed, creating the new unpaved road sur- face that was then treated with a dust suppressant. The road was converted because of cost of maintaining the road and safety concerns. ADT on the road is 21 to 50 vehicles. At this time the road is performing well, has saved the county money, and has required less maintenance than anticipated. Public reaction to the road conversion has been both positive and negative, and there has been pressure to repave the road. Outreach efforts included public meetings that were deemed somewhat success- ful. Kingsbury County found working with the local technical assistance program and state officials and having a consulting engineer on hand for questions and answers during the public meeting to be helpful. Kingsbury County has plans to convert more roads from paved to unpaved in the future. Within the last year (2014–2015), in McCook County, South Dakota, 3 mi of road with asphalt concrete in poor condi- tion and an ADT of 51 to 100 vehicles were converted to an unpaved road with surface stabilization incorporated into part of the surface layer. They added clay to tighten up the surface, which resulted in more dust, but the public preferred dust over a loose surface with an asphalt/gravel blend. The road was converted because of cost of maintaining it. Information used to support the decision to convert the road included traffic counts, road core information, and a basic grid design plan that involved having residents within 4 mi of an asphalt road. The converted road is performing well and has saved the county money but is requiring more maintenance than anticipated. There has been no increase in documented vehicle crashes on the converted road. Public reaction to the road conversion has been negative. Outreach efforts were made, including public input meetings. There has been no pressure to repave the converted road. In the future 17 mi of asphalt concrete road in poor condition in McCook County will be converted to gravel once it has reached the end of its service life. UTAH In Tooele County, Utah, approximately 13 mi of local access connector roads have been converted from paved to unpaved within 1 to 2 years (2012–2013). The original pavement sur- faces consisted of asphalt concrete in poor condition and cold mixed asphalt with a chip seal. They rented an asphalt reclaimer and recycled the old surfacing into the unpaved road, then used a surface application of 28% magnesium chloride as a dust pal- liative (applied at about 0.5 gal/yd2). The road has an ADT of 100 to 150 vehicles and was converted from paved to unpaved because of the high cost to maintain it and safety concerns. To support this road conversion project, Tooele County has con- ducted a pavement inventory analysis since 1988 and because of limited funds prescribe to a “treat your best roads first policy.” They determined it was less expensive to convert the road to gravel than it would have been to repave. The converted road is performing as expected, but they have found the cost of spraying magnesium chloride is now cost prohibitive, so there will be more dust this year (2015). Tooele County did hold an informal meeting as outreach to the public and deemed this effort a success because the peo- ple knew what was happening. Despite these efforts, reaction to the road conversion was negative because the public did not like that the road was being converted. Part of the dislike for the road conversion was because local residents access a water ski lake using the road and do not like towing boats on the gravel road. Consequently, there has been pressure to repave the road. One of the challenges they faced in converting this road was that it varied in thickness because there were many older roads underneath that had already been milled at least once. There was no geotechnical information on the thickness vari- ation, which made it challenging. Based on this experience, they will consider collecting core samples before any future roads conversion projects. As a side note, Tooele County instituted a municipal service fee for the unincorporated county, and the state of Utah just raised the gas tax and has given counties the option to institute a local gas tax, which could be used to fund local roads projects. VERMONT Within the city limits of Montpelier, Vermont, 1.25 mi of asphalt concrete that were in poor condition (PCI = 1, on a scale of 0–100) were converted to an unpaved surface of recycled asphalt, concrete, and crushed gravel mix. The old surface was recycled, new gravel was hauled in to supplement the existing material, and a chemical stabilizer/dust suppressant was used. The decision to convert the road to unpaved was because of the cost to maintain the road as an asphalt surface treatment in addition to the request to do so by a group of residents living on the road. Average daily traffic on the road was 300 to 500 vehicles. The conversion was performed 5 or more years ago (prior to 2010) using repaving equipment the agency has on hand. Converting the road required using a recycling machine, spot repairs, grading, and placement or repair of culverts and ditches. The recycled asphalt was stockpiled and supplemented with crushed reclaimed asphalt

73 pavement, with a goal of 50/50 mix of underlying gravel with the recycled asphalt. When converting the road, compaction was difficult ini- tially, and the city ended up using a compaction aid and dust suppressant–flake/pellet calcium chloride (CaCl2). The con- verted road required typical gravel road winter maintenance, not reapplication of chemicals, but instead placement of trac- tion materials. The converted road is performing well. Ulti- mately, the road agency saved money by converting the road, requiring less maintenance than anticipated. There has been no increase in documented vehicle crashes, and overall the public reaction to the conversion has been positive. To involve the public, a letter was sent to road users (see Appendix F), and a public hearing was held. Once the road conversion was completed, they held another public hearing to address initial concerns, such as dust control. At the follow- up hearing, people were supportive, even motorcyclists. All of these public outreach efforts worked well and were considered successful. There has been no pressure to repave the road. This was a good lesson for the road agency to consider in future conversion projects, including involving the public early in the process and having a conversation with road users about the reality that the road would not be repaved and so they needed to consider potholes or gravel. ONTARIO, CANADA In Ontario, Canada, 2 center-line mi from three paved roads were converted to unpaved by recycling the old surface and incorporating it into the new road surface. New gravel was hauled in to supplement existing materials, and a dust suppres- sant surface treatment was applied and incorporated into the surface layer of the new road. The pulverized road surface was overlaid with 3 in. of gravel, but they prefer crusher run granite, so they added magnesium chloride and pulverized it again to mix it thoroughly. After this, a smooth drum roller was run over the surface before opening the road to the public. The road was converted because of the costs to maintain the road and com- plaints from the public. A budget limitation investigation was conducted to determine if low-volume traffic roads with paved surfaces in bad condition could be converted to gravel at an affordable cost. The roads were identified for conversion based on high maintenance costs, mostly associated with patching; the worst roads were identified, and treatment options were explored. The road has an ADT of 50 to 100 vehicles and was converted less than 1 year ago (2013–2014). They are currently conducting a 2-year study to determine how the converted road performs, and if this is a viable option for the future. At this time the converted road is performing well, and there has been no documented increase in vehicle crashes. Initially there was some concern from a few members of the public about the use of magnesium chloride and the road conversion, but in the end the public reaction to the road con- version has been positive, in part because of outreach efforts, which included a successful meeting with ratepayers in one cottage association. Some complaints have been received about frost heaving on the converted road in the spring. There has been some pressure to repave because of concerns about stone chips on cars. At this point in time they have plans to convert an additional 0.7 mi of road in 2015. REFERENCES FOR APPENDIX D American Association of State Highway and Transportation Officials (AASHTO), Guidelines for Geometric Design of Very Low-Volume Local Roads, AASHTO, Washington, D.C., 2001. Shearer, D.R. and B.E. Scheetz, “Improvements to Linn Run Road: Case Study on Turn-Back of Asphalt-Paved Road Sur- face to Maintainable Gravel Road Surface,” Transportation Research Record: Journal of the Transportation Research Board, No. 2204, Transportation Research Board of the National Academies, Washington, D.C., 2011, 215–220.

Next: Appendix E - Additional Examples of Road Conversion Projects from Paved to Unpaved »
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TRB’s National Cooperative Highway Research Program (NCHRP) Synthesis 485: Converting Paved Roads to Unpaved explores how common and under what conditions paved roads are converted to unpaved.

NCHRP Synthesis 485 found that the practice of converting paved roads to unpaved is relatively widespread; recent road conversion projects were identified in 27 states. These are primarily rural, low-volume roads that were paved when asphalt and construction prices were low. Those asphalt roads have now aged well beyond their design service life, are rapidly deteriorating, and are both difficult and expensive to maintain. Instead, many local road agencies are converting these deteriorated paved roads to unpaved as a more sustainable solution.

According to the report, local road agencies have experienced positive outcomes by converting roads. Many local road agencies reported cost savings after converting, compared with the costs of continuing maintenance of the deteriorating paved road, or repaving. One key to successful conversion is early involvement of the public in the planning process. Other techniques that can be used to improve the overall results of a project include treating or stabilizing granular surfaces to control dust, limiting the rate of aggregate loss, and reducing motor grader/blade maintenance frequency. Stabilization procedures can also improve safety, increase public acceptance, and reduce life-cycle costs and environmental impacts after a conversion has taken place.

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