N.H. expands rumble strips on state roads, to some neighbors’ annoyance

  • Rumble stripes, shown on Route 9, allow more room for bicyclists but give drivers less of a buffer. GEOFF FORESTER / Monitor staff

  • A rumble streip million machine by L&D Safety Marking of Barre, Vt. It drives along at about 3 mph, cutting grooves into pavement. The tank holds water to hold down dust. Courtesy—L&D Safety Marking

Monitor staff
Published: 6/18/2016 12:15:12 AM

They’re called rumble strips, or “rumble stripes” when covering painted lines, and the jolt of noise they produce as drivers drift out of their lane has long been part of life on interstate highways. But as New Hampshire begins expanding the system to smaller roads, complete with center-line grooves, some of the rumble is coming from annoyed neighbors.

“The noise, it’s absolutely amazing . . . when cars go over them,” said Sylvia Leggett, co-owner of Roberts Knoll Campground in Alton, which for 14 years has been on Route 28, where the Department of Transportation recently had grooved patterns dug into the centerline and both shoulders. “We understand the traffic noise, but we don’t expect the rumble strips. . . . They can hear it down to Lake Winnipesaukee in one area.”

The campground is holding a meeting June 22, at 7 p.m. to rally against what Leggett calls the creation of “Rumble Strip Alley.” A forum is being formed on the same topic in Plymouth, where rumble strips are planned on Route 3A, and people living around Henniker and Hopkinton will recognize the issue from years of debate about rumble strips on Route 202.

Those Route 202 rumble strips, installed in 2008 as an experiment during repaving of a dangerous stretch of road sometimes called “Death Alley,” are an indirect cause of the current program for cutting rumble strips into center lines, and sometimes shoulders, of many state roads.

The $30,000 application of rumble strips on Route 202, he said, reduced crashes by one-third and crashes with fatalities by 46 percent over the following four years by reducing the biggest source of accidents: drivers who strayed into oncoming traffic or drive off the road. This led New Hampshire to expand the program beyond the limited-access highways where they have long been used, said Ron Grandmaison, an engineer for the New Hampshire Department of Transportation.

This summer, rumble stripes are being cut along four major state roads, including most of Route 9 from Concord to Chesterfield, and over the next five years will be put on many other relatively high-speed roads (40 mph or greater). That includes Route 4 from Salisbury east to Dover. Like many roads to be marked, it has an east-west orientation, meaning drivers can be blinded by the sun during morning and afternoon commutes.

Putting rumble strips on two-lane roads is relatively new for New Hampshire.

“This is really the first project of its type that is on more of a rural facility,” said Grandmaison, the state’s go-to guy for the topic.

“It’s not just New Hampshire; it is national,” he said of this expansion. “I’ve been to a couple of seminars, with technical advisory committees; 30-plus states are doing them all over the place, are testing them, see what design works best, the minimum depth, width, what alternatives work.”

The company that won the $385,000 contract to install the strips in New Hampshire this year, L & D Safety Marking Corporation, of Barre, Vt., has expanded into the rumble strip business after three decades of painting road stripes because of their effectiveness.

“You get the noise, and you also get better visibility at night in wet conditions – it exposes the front face of paint, (reflective) glass beads, so they’re not totally covered underwater,” said Gray Ricker, owner of L&D.

“Before it was done on interstate shoulders and that was it. There were a few contractors who traveled around.
. . . Now it’s being done on all sorts of different roads,” said Ricker. “Center-line rumble strips have been debated over many, many years, but the thinking has totally changed. . . . Now it’s being done around the country.”

Rumble strips are cut into pavement by a device with the appropriate name of Rumble Strip Grooving Truck, which travels at about 3 mph cutting grooves of varying widths and depths, depending on their location, Ricker said. It is followed by a sweeper to gather up asphalt debris and put it in a dump truck.

“They just cruise down the road,” Ricker said.

The Federal Highway Administration supports rumble strips as a low-cost safety technology, but admits they have drawbacks.

Bicyclists, for one, are leery.

“When not installed properly, rumble strips can be a serious danger to cyclists’ safety. Rumble strips can force cyclists into the travel lane with high speed traffic when installed on roads with little or no shoulder or down the middle of the existing shoulder,” says the Adventure Cycling Association.

“We loosened (standards) a bit, updated them again because of outcry from bicycling community,” said Grandmaison.

That concern is why the shoulder rumble strip known from interstates – 16-inch-wide grooves, installed in the middle of the shoulder about 2 ½ feet away from the painted edge of the travel lane – is mostly replaced on rural roads with a rumble stripe. Those are 12 inches wide and cut directly over the highway’s edge stripe (which is repainted afterward), leaving bicyclists at least four feet between them and the edge of the pavement, or at least five feet if there’s a guardrail.

This change may please bicyclists but it can irritate drivers, who are jolted by a rumble from their tires with the slightest departure from the travel lane.

Leggett of Roberts Knoll Campground said she has heard this concern from drivers, who feel the center grooves and shoulder grooves on Route 28 are too close together, not always leaving the minimum 12-foot-wide lane.

The state’s rumble strip guidelines (online at nh.gov/dot/org/projectdevelopment/highwaydesign/rumble-strips/index.htm) were updated in 2015 in preparation for this year’s work.

“We didn’t really have any established guidelines for putting them on roadways that are not interstates. There was a great outcry when we installed them (in 2008) . . . people saying (things like) they wake us up in the middle of the night,” Grandmaison said. “Due to the outcry, the department said, instead of just installing these we needed to establish guidelines.”

These guidelines include details about where not to place the grooved markers – for example, stopping at least 25 feet away from intersections and providing “gaps of 12 inches in the shoulder rumble stripes every 48 inches” for bicyclists to maneuver.

They don’t, however, say exactly where to place rumble strips. That’s a judgment call, based on traffic, the characteristics of the roadway and the experience of people working along the roads, Grandmaison said.

New Hampshire, like many states, is experimenting with designs of rumble strips, including sinusoidal rumble strips. Named after the mathematical shape known as a sine wave, these have a wavy cross section rather than the usual square cut of grooves, so that cars going over them make less noise – hence their punning nickname “mumble strips.” Whether they make enough noise to alert drivers is still up in the air.

One design that New Hampshire is not studying are “musical” rumble strips, where grooves are spaced in such a way that driving over them creates the recognizable rhythm of a well-known song. A number of such creations exist around the world.

As for Grandmaison, he knows that concern about rumble strips will continue, but he thinks the safety benefits are worth it.

“Nobody’s going to come beating on the door saying, ‘Hey, you saved my life today, thank you!’ ” Grandmaison noted, but he’s sure this happens, pointing to his own experience.

On a recent long-distance trip, he says, his wife dozed off while driving as he was sleeping after trading off driving chores; both were awakened by a rumble strip.

“If it wasn’t for that, I’m sure we’d be dead,” he said.

(David Brooks can be reached at 369-3313, or dbrooks@cmonitor.com or on Twitter @GraniteGeek.)

David Brooks bio photo

David Brooks is a reporter and the writer of the sci/tech column Granite Geek and blog granitegeek.org, as well as moderator of Science Cafe Concord events. After obtaining a bachelor’s degree in mathematics he became a newspaperman, working in Virginia and Tennessee before spending 28 years at the Nashua Telegraph . He joined the Monitor in 2015.

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