Derry Road Maintenance System Explained to Council

Derry Public Works (DPW) Director Mike Fowler flicked on a slide. “This condition is called ‘rutting,’” he said of a paved road filled with furrows. “This road actually had a 7-inch depression at one spot.”

Fowler and Derry Highway Supervisor Alan Cote spoke at the Sept. 17 Town Council meeting to explain their highway maintenance system and how they decide which roads get attention, and when.
Fowler’s system relies heavily on data gathering, he said as he narrated a PowerPoint presentation. He uses a rubric called a Pavement Control Index (PCI), 
The town does a survey of road conditions every three years, Fowler said. It determines the cost implications and measures them against the DPW budget, then projects the needs over five years. “The system stores, manages and calculates the data,” he said.
Field surveys are done by Engineering Technician Dave Belanger and are then entered into the database. The software evaluates the data and generates a PCI for each road. They use a computer program called “Road Manager,” Fowler said.
Belanger looks for and enters conditions including longitudinal cracking, transverse cracking, raveling and rutting, and something called “alligator cracking,” Fowler said.
The Town Council supports a “pay as you go” policy, Fowler said, and because of that, the town hasn’t had to bond for routine road improvements. The amount allotted by the town ranges from $1.2 million to $1.4 million each budget cycle. The town receives a $581,000 Community Block Grant from the state for roads, but that covers only a fraction of the needs, Fowler said.
When the funding isn’t there, the PCI declines, Fowler said. And in recent years, he’s found his pavement dollar doesn’t go as far.
“Asphalt is up 167 percent,” he said. “It was $26 to $30 a ton in the 1990s. It’s now $75 a ton. We have the same amount of money, but what we’re able to do with it has declined.”
His goal, he said, is to “give the right treatment to the right road at the right time.” This means one of three treatments: reclaiming, including pulverizing the pavement, adding a new gravel base and repaving over it; mill, shim and overlay; or just shim and overlay. The last two are less costly than a complete reclamation, but if the issues are caught in time, are adequate.
“We also have to consider the drainage, base material and traffic volume,” Fowler said. “Is the traffic local, collector, arterial?”
He also makes an effort to coordinate road repairs with construction projects. “If utilities are to be upgraded, that’s done first so we don’t have to pave twice,” he said.
Time is essential in Derry roadwork because of the short paving season, Fowler said, adding, “We attempt to go forward as quickly as we can.”
But the systematic approach and the computer-managed data works for Derry, he said, noting, “You don’t see us chasing potholes like you do in other communities.”

Both comments and pings are currently closed.

Comments are closed.