Rural roads. Gravel or asphalt?
February 12, 2019 5:41 AM Subscribe
Over time, including installation, maintenance, plowing , everything -which is more cost effective- asphalt or gravel?
The roads in question are in rural, small town NH, USA. Strictly in terms of money, should we re-pave a mile of asphalt road or leave it as gravel?
The roads in question are in rural, small town NH, USA. Strictly in terms of money, should we re-pave a mile of asphalt road or leave it as gravel?
Some places are tearing up asphalt and replacing it with gravel to lower their maintenance costs -- example. It's cheaper on the road construction and maintenance side, but more expensive in terms of wear and tear on people's vehicles.
posted by Dip Flash at 6:21 AM on February 12, 2019
posted by Dip Flash at 6:21 AM on February 12, 2019
I would expect this question highly depends on some other factors as well like how is the drainage situation along the length of the road and do you already own a tractor and box blade for grading the road whenever it needs it (or are you game to purchase one or both if that's something you'd have a use for otherwise) or would you be hiring out all of the same, such as patching the inevitable potholes in either surface, also the composition of the subsurface probably matters a fair bit as well. I'd get a consult or quote or two for up front costs and then go from there regarding how you want to attempt to calculate/estimate maintenance costs for either option. Folks here can help but you'll need boots on the ground / paper figuring to get a really useful answer here.
posted by RolandOfEld at 6:51 AM on February 12, 2019
posted by RolandOfEld at 6:51 AM on February 12, 2019
There is a funny book by Don Mitchell titled Moving Up Country about a couple moving to Vermont in the 70s. There is a bit in the story about a flatlander who stands up at Town Meeting Day and asks why the town doesn't pave more of it's roads and the selectperson replies with "Because the town has a gravel pit and doesn't have an oil rig." (paraphrasing)
Lots of good answers above. It really depends on other conditions. Is it on ledge? How does it drain? Is it susceptible to frost heaves? etc.
posted by terrapin at 7:05 AM on February 12, 2019 [1 favorite]
Lots of good answers above. It really depends on other conditions. Is it on ledge? How does it drain? Is it susceptible to frost heaves? etc.
posted by terrapin at 7:05 AM on February 12, 2019 [1 favorite]
I can drive 55 mph down an asphalt road with no problems (assuming it is in good condition).
Or I can inch down a gravel road and hope that I don't put a hole somewhere it doesn't belong. Also, lots and lots of dust.
Gravel migrating to the shoulders will fill in the ditches, which causes the road to be flooded at the low spots. This also means icy roads in the winter.
Deep ruts in the road turn into slick clay in the rain. More gravel slides to the bottom of the hill, so getting to the top of that hill with lower traction is a problem.
Meeting vehicles (like school buses) and having clearance is a problem. Trying to swerve or stop before hitting a cow or a deer or a dog is a problem. Riding a bicycle or a motorcycle is a problem.
Someone else needs to weigh in on road surfaces and horses.
I am assuming there are no concrete bridges on this stretch of gravel road. Tin horns over ditches can be uncovered.
Rural asphalt and concrete roads take a beating when they are used by big rigs transporting heavy equipment and large loads (oil and gas trucks, timber, mining, construction, etc.) Patches are a temporary solution, and a complete resurfacing can disrupt local transportation when there are few, if any, alternative routes.
Sure... bringing out a truckload of gravel is faster and uses less workforce to accomplish. But it doesn't solve the problem of having a safe surface to drive on in all types of weather. Rural people drive at night, too.
And the neighbors would like to leave their windows open and put clothes on the line without choking on all that dust.
Disclaimer: my father worked in road construction through most of his professional career, 1940s to 1980s.
posted by TrishaU at 7:15 AM on February 12, 2019 [4 favorites]
Or I can inch down a gravel road and hope that I don't put a hole somewhere it doesn't belong. Also, lots and lots of dust.
Gravel migrating to the shoulders will fill in the ditches, which causes the road to be flooded at the low spots. This also means icy roads in the winter.
Deep ruts in the road turn into slick clay in the rain. More gravel slides to the bottom of the hill, so getting to the top of that hill with lower traction is a problem.
Meeting vehicles (like school buses) and having clearance is a problem. Trying to swerve or stop before hitting a cow or a deer or a dog is a problem. Riding a bicycle or a motorcycle is a problem.
Someone else needs to weigh in on road surfaces and horses.
I am assuming there are no concrete bridges on this stretch of gravel road. Tin horns over ditches can be uncovered.
Rural asphalt and concrete roads take a beating when they are used by big rigs transporting heavy equipment and large loads (oil and gas trucks, timber, mining, construction, etc.) Patches are a temporary solution, and a complete resurfacing can disrupt local transportation when there are few, if any, alternative routes.
Sure... bringing out a truckload of gravel is faster and uses less workforce to accomplish. But it doesn't solve the problem of having a safe surface to drive on in all types of weather. Rural people drive at night, too.
And the neighbors would like to leave their windows open and put clothes on the line without choking on all that dust.
Disclaimer: my father worked in road construction through most of his professional career, 1940s to 1980s.
posted by TrishaU at 7:15 AM on February 12, 2019 [4 favorites]
If you're trying to make this decision for real rather than hypothetically, I think this is a situation where it would probably be well worth it in the long run to pay for a consultation with a licensed civil engineer. The savings to your town for making the right calls in the right places would probably greatly outweigh the cost of the consultation.
posted by Anticipation Of A New Lover's Arrival, The at 7:37 AM on February 12, 2019 [2 favorites]
posted by Anticipation Of A New Lover's Arrival, The at 7:37 AM on February 12, 2019 [2 favorites]
Chip seal is becoming popular on rural roads ... supposedly the best compromise between durability and cost (especially for repair). But it’s pretty much unrideable for bicycles, if that matters to you.
posted by wutangclan at 7:41 AM on February 12, 2019 [2 favorites]
posted by wutangclan at 7:41 AM on February 12, 2019 [2 favorites]
Is rubberized asphalt / Crumb Rubber Modified asphalt an option?
“CRM-built roads last longer and require less maintenance. Because of its elastic nature, it can sustain the dynamic stress caused by traffic without showing cracks or dents. Since water does not accumulate in cracks, the roads are not affected by the freeze-thaw effect in winter. CRM’s initial cost is approximately 20% higher than conventional asphalt. However, the savings on labor for installation and the reduced maintenance pay off the extra cost in a short time. The cost of CRM has been dropping since 1992, when the patent on CRM expired.” (source)
posted by D.Billy at 7:47 AM on February 12, 2019
“CRM-built roads last longer and require less maintenance. Because of its elastic nature, it can sustain the dynamic stress caused by traffic without showing cracks or dents. Since water does not accumulate in cracks, the roads are not affected by the freeze-thaw effect in winter. CRM’s initial cost is approximately 20% higher than conventional asphalt. However, the savings on labor for installation and the reduced maintenance pay off the extra cost in a short time. The cost of CRM has been dropping since 1992, when the patent on CRM expired.” (source)
posted by D.Billy at 7:47 AM on February 12, 2019
Best answer: Depends mostly on the amount of traffic the road must sustain, and whether that level of traffic will make regrading the gravel on an ongoing basis more expensive than infrequent paving.
In Southwestern Ontario, which is also subject to significant winter weather, there is a vast grid network of gravel roads throughout the agricultural areas. These are maintained in quite good condition with re-ditching, grading, rolling -- and plowing in the winter months. This network of gravel roads, 1000s of kms of them, support farm equipment and transports when necessary to move produce, as well as regular vehicular traffic.
When the traffic levels on a particular stretch become too high for this to support, you get bearing and shock-destroying washboarding and erosion that can lead up to "water features" that will eat axles. Those sections get paved, with several layers (not the cheapest paving).
Anyway, both gravel and asphalt roads need good foundations. Probably it makes sense to clean up the road and turn it into gravel and watch it for a year, including over a winter, and see how it survives.
posted by seanmpuckett at 8:12 AM on February 12, 2019 [3 favorites]
In Southwestern Ontario, which is also subject to significant winter weather, there is a vast grid network of gravel roads throughout the agricultural areas. These are maintained in quite good condition with re-ditching, grading, rolling -- and plowing in the winter months. This network of gravel roads, 1000s of kms of them, support farm equipment and transports when necessary to move produce, as well as regular vehicular traffic.
When the traffic levels on a particular stretch become too high for this to support, you get bearing and shock-destroying washboarding and erosion that can lead up to "water features" that will eat axles. Those sections get paved, with several layers (not the cheapest paving).
Anyway, both gravel and asphalt roads need good foundations. Probably it makes sense to clean up the road and turn it into gravel and watch it for a year, including over a winter, and see how it survives.
posted by seanmpuckett at 8:12 AM on February 12, 2019 [3 favorites]
Best answer: Asked my Dad, who ran a road crew in Canada for decades, he says in his experience gravel is much, much cheaper and that they would convert gravel to asphalt as they could afford it and on the busiest roads.
posted by Cosine at 8:52 AM on February 12, 2019 [1 favorite]
posted by Cosine at 8:52 AM on February 12, 2019 [1 favorite]
In NZ we have many thousands of kilometers of gravel (here called metal) roads, they are constructed to a hierarchy of standards and you certainly don't have to inch along them - you do have to learn how to drive on gravel tho' so they are better for local roads. Most are posted at 100\kmh and they are certainly more comfortable above 75kmh, as corrugations develop.
Most are regraded yearly\two-yearly and they're generally fine and fun to drive on - they are definitely easier to drive on with light snow or ice than asphalt. They can also be set up to drain thru the surface (specific design required). Most regions here have a moratorium on extending the tar-sealed network as oil price volatility you had been making this a no go. There is an annual engineeringconference on unsealed road design down here too.
posted by unearthed at 10:28 AM on February 12, 2019 [2 favorites]
Most are regraded yearly\two-yearly and they're generally fine and fun to drive on - they are definitely easier to drive on with light snow or ice than asphalt. They can also be set up to drain thru the surface (specific design required). Most regions here have a moratorium on extending the tar-sealed network as oil price volatility you had been making this a no go. There is an annual engineeringconference on unsealed road design down here too.
posted by unearthed at 10:28 AM on February 12, 2019 [2 favorites]
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This article lays out a decision process that seems fair and climate- appropriate for NH, albeit from an agency point of view. One interesting finding is that extremely low volume roads have a far lower lifecycle cost with asphalt.
posted by q*ben at 6:14 AM on February 12, 2019 [3 favorites]