By KAREN GARDNER
The Frederick News-Post
FREDERICK, Md. - For Susan Hanson, the gravel roads of Frederick County lead to a slower time and place.
The roads, which she compares to linear parks, are places where people often walk their dogs or ride their horses. Painters occasionally set up their easels in the middle of a gravel road. Photographers chase wildlife scenes.
The Frederick County Rural Roads Program is celebrating its 10th anniversary this year with a series of events to showcase the value of gravel roads.
Gravel roads were once the norm in Frederick County. Even in the 1970s, there were 400 miles of gravel roads in the county. Today, out of 1,300 miles of county-maintained roads, about 60 miles of gravel roads remain.
"I've always loved gravel roads," Hanson said. "I grew up in D.C. but went horseback riding in Potomac. Lots of places that are now huge roads were gravel back then."
Gravel roads make drivers slow down. In 35 years of living on Poffenberger Road, Hanson can't remember any wildlife being struck, much less any people.
Gravel roads are much safer for pedestrians and cyclists, she said. Cars and trucks can easily be heard as they roll through gravel, and they're traveling much more slowly. Cyclists and horseback riders can focus on scenery, not traffic.
"They are an incredible gem this county has," she said.
Yet, as old-fashioned as gravel roads are, there's a modern twist to one of them.
Hanson's road, Poffenberger Road, is part of an experiment, which goes to prove that even something as old school as a gravel road can get a boost from technology. Pennsylvania, which has 20,000 miles of unpaved roads, is home to the Penn State Center for Dirt and Gravel Roads Studies. The center has developed environmentally sensitive maintenance, or ESM, practices for unpaved roads and trails.
A few years ago, the Frederick County Commissioners decided to see if the Pennsylvania experts could give the county some tips on gravel road maintenance. They decided to experiment on a one-mile section of Poffenberger Road, a section that runs by Hanson's house.
Experts from the center recommended a special mixture of crushed limestone to cut down on dust and sediment runoff into streams. Using gravel from a Frederick County quarry, the experimental section of road was laid in June and July 2009. The result is a smoother gravel surface with better drainage, Hanson said.
The local project is called the driving surface aggregate, or DSA, demonstration project. DSA has its roots in the prime brook trout streams area of Pennsylvania. In those streams, the primary pollution was gravel, clay, dirt and other particulates that get mixed up into a gravel road, according to David Olney, project manager in the county's Office of Transportation Engineering.
Unlike most gravel, which has bits of clay in it, DSA is all stone, Olney said. "It's a specific mix of different sizes of stone," he said. "It looks like flour or dust, but under a microscope, it's jagged pieces of stone, fitted together like pieces of a jigsaw puzzle." This means there are no gaps between the stones, which allows the material to compact better than traditional gravel.
It also results in much cleaner surroundings, according to Olney. The ESM roads have a better drainage system, which prevents runoff. There isn't the dust that often coats nearby vegetation, nor is there gravel runoff into nearby streams. Hanson said she has much less dust in her house since DSA was installed.
Although there were some kinks in the installation process, the DSA has been found to perform better than regular gravel and doesn't deteriorate as quickly, Olney said. The problem is, it's still pretty expensive. He estimated it would take 30 years to recoup the approximate $100,000-per-mile cost.
Pennsylvania, which uses the ESM practices for gravel roads throughout the state, has a different funding structure, using a portion of the gas tax to pay for the improvements. Also, many of Pennsylvania's gravel roads are in pristine forested areas, not agricultural areas as most of Frederick County's gravel roads are.
"It is a step in the right direction," he said. But the benefits do not outweigh the costs, so the DSA project likely won't be expanded in the near future.
In the 1990s, Frederick County's gravel roads were supposed to be covered with macadam or tar and chip, a material that is denser than gravel but not as smooth as asphalt. Hanson and a few others who lived along the county's rural roads weren't happy and asked the county to reconsider. The Frederick County Rural Roads Program was proposed in 1999 and approved in 2002.