Surface economy: pavement vs. gravel roads

Highland Road in Old Chatham. Photo by David Lee

GHENT—The radio commentator Paul Harvey famously wrote: “What’s mainly wrong with society today is that too many Dirt Roads have been paved. There’s not a problem in America today—crime, sex, education, divorce, delinquency—that wouldn’t be remedied if we just had more Dirt Roads, because Dirt Roads give character.”

Most of the county’s residents have similarly strong opinions on whether to see more town roads paved or left as gravel.

The arguments are familiar: dirt roads fit the rural character of the area; dirt roads spawn mountains of dust; paved roads encourage traffic and speeding; paved roads are safer; dirt roads create safety hazards; paving roads is expensive; maintaining dirt roads is expensive; paved roads are easier on vehicles. And so on.

Perhaps the strongest argument for maintaining dirt roads (which usually means gravel roads) is their significance as a marker of rural character. The Chatham Dirt Road Coalition, for example, says that “dirt roads are a heritage worthy of preserving for many reasons: they provide a safer place for exercise and recreation than faster paved roads, they enhance the natural beauty of our landscape, and in a very real way they are a living connection to our history.” The coalition’s website includes a hand-drawn map illustrating the more than 40 miles of dirt roads in Chatham.

Ghent Highway Superintendent Benjamin Perry would echo the thought that dirt roads embody local history—literally. Dirt roads were initially little more than cow paths leading to farms over which milk trucks passed. In the process of improving or paving old dirt roads, his department has found logs, tree stumps, engine blocks and other car parts and even a cow stanchion, in the road beds.

But the dirty truth about dirt roads, according to Austerlitz Highway Superintendent Peter Fitzpatrick, is that they have a poor ecological record. He cites studies showing that gravel roads lose an inch of dirt every year; and, that dirt is not only to be found on cars, but on windows and window sills. Unpaved roads are generally so compacted that very little water soaks in. Instead, rainwater runs off, carrying sediment into watercourses.

Sediment can smother stream habitats, reducing biodiversity, especially affecting the spawning and rearing of trout. Runoff can raise streambeds and exacerbate flooding. It can also harm roadside vegetation. Nutrients and sediments reaching sensitive water bodies can adversely affect water quality.

Safety is another concern. While the highway superintendents agree that a well-constructed and maintained gravel road is as safe as a paved road nine months of the year, when it comes to mud season. Then, roads may turn so mushy as to be impassable for heavier vehicles like school buses and fuel trucks. As Fire Chief Brennan Keeler of Claverack notes, sometimes dirt roads are too narrow for his vehicles to pass one another and in mud season the roads may not support trucks, making passage impossible and creating real safety issues.

Residents also complain that a paved road leads to more traffic and speeding. Mr. Fitzpatrick might agree but he notes that drivers speed on dirt roads also and wonders whether the potholes and rutting that is inevitable do not create greater driving hazards.

Snow removal and melt varies according to surface. Blacktop is generally cleared of snow more quickly as the snow will melt more rapidly on it, but if the surface is wet it can freeze to black ice. If the air is cold, a gravel surface will resolve to snow pack which is relatively safe and easy for snow plows to travel, whereas driving on mushy snow on a gravel surface is jarring on vehicles and drivers alike.

Another key difference is financial. Maintaining gravel roads is an expensive proposition. According to Superintendent Fitzpatrick of Austerlitz (whose town roads, like many county towns, are predominantly gravel-surfaced), a gravel road requires grading at least once and sometimes three and four times every year. To grade, trucks make four to eight passes at two miles per hour, not even counting spot treatments for potholes and other problem areas. One full day of grading requires a grader, a roller and a water truck. Gravel has to be hauled to the site. Austerlitz uses some 5,000-6,000 tons of gravel each year. The trucks consume 60-100 gallons of fuel/day. At least two workers are needed. After grading, the surface must be watered and a chemical (generally considered safe) called calcium chloride is applied to harden the surface and diminish dust. Vehicles maintaining and snow-plowing gravel roads themselves need more maintenance than their counterparts working on paved roads.

By contrast, paved roads require little maintenance. Ghent Superintendent Perry notes that all but 2 miles of the 77 miles of Ghent town roads are paved, either with blacktop or “pugmill,” a mixture of stone, water and an emulsion. Blacktop has a 20-25 year “life expectancy” and pugmill a 15-18 year life. Neither requires annual maintenance, other than the tree-clearing, ditch-cleaning and mowing that all roads require. Superintendent Perry estimates that a highway department will spend 80% or more of its “time and energy” on dirt roads.

However, the cost of installing a paved road is significant. Before you can pave, the road drainage often must be upgraded, with the installation of new pipes and culverts, to divert water away from the roadbed. A good gravel road must be laid, graded and shaped to a gentle crown. Assuming the drainage has been attended to, Superintendent Perry estimates that the cost for one mile of a pugmill road is $150,000 and of blacktop $200,000 or more. (Which surface to use is not only a question of cost, but also the underlying conditions; blacktop is not recommended in areas that suffer frost heaves, whereas pugmill will expand and contract with temperature changes.)

Direct costs to road residents also vary depending on road surfaces. A study by the University of Kentucky found that the cost of operating a vehicle on a gravel surface is often two to three times greater than on a paved surface because there is “greater rolling resistance and less traction” on gravel which increases fuel consumption, there is additional tire wear, and dust affects oil consumption and engine maintenance costs.

Finally, a June 2021 Rural Dirt Road Assessment prepared for three South Berkshire towns found that many of the considerations are shifting with climate change. With the increase in stronger and more frequent storms, the reduction in the number of days below freezing and delays in winter freezing and with earlier spring thaws, dirt roads have become even more vulnerable. The increase in extreme weather events leads to more intense runoff and even landslides and occasional washouts. With added freeze-thaw events occurring, we sometimes now experience multiple “mud seasons.” Pandemic-driven population growth also affects the roads, not only leading to greater traffic but also the presence of more heavy construction and delivery vehicles, which accelerate road degradation.

So, to pave or not to pave: it’s complicated.

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