'Traffic Calming' Rounds a Curve

'Traffic Calming' Rounds a Curve

Residents express support for the idea of traffic calming on Hunter Mill Road.

"I don't want you to think that if you raise your hands, we're just going to plow ahead with this, but are we on the right track?" Mark Gibb asked toward the end of a meeting convened to discuss traffic calming concepts for Hunter Mill Road last Wednesday, May 24. Almost all of the 150 or so residents who were gathered in the auditorium of the Unity of Fairfax Church raised a hand in approval.

Asked for dissenting votes, the audience produced about half a dozen protesting hands. Gibb is the executive director for the Northern Virginia Regional Commission (NVRC), the governmental arm assigned to oversee the spending of $75,000 allocated by the state legislature for a study of possible traffic calming measures for Hunter Mill Road.

The commission contracted engineering and surveying consultants Draper Aden to conduct the study, and Draper Aden, in turn, subcontracted Michael Wallwork, head of Alternate Street Design, P.A. and specialist in the practice of traffic calming and designing roundabouts. Wallwork hails from Australia, where roundabouts abound.

Wednesday evening, Wallwork offered residents of the seven-and-a-half-mile Hunter Mill corridor a presentation put together by himself, Draper Aden and NVRC.

He was met with no shortage of questions and concerns, but there was little outright opposition to the idea of using such measures as medians, splitters, landscaping and a series of roundabouts — rather than the traditional methods of adding lanes and stoplights and straightening and flattening the roadbed — to deal with heavy traffic, chronic speeding and numerous blind spots on the winding thoroughfare.

One reason nontraditional methods have long been advocated by many of those who are active in the community — including the Hunter Mill Road Traffic Calming Committee, comprising residents who were selected by the Board of Supervisors to advise the project — is that the road lies in a corridor that includes some 31 points of historic interest and, as a designated Virginia Byway, is eligible for nomination to the state and national historic registers.

Four-lanes would not only compromise the historic character of the road but would threaten the surrounding historic sites, Wallwork would later explain. "Which comes first, the development or the road," he asked. He characterized the future of the road as "a tug-of-war between residents who want to keep a historic place to live and developers who want to just line the place with development."

"THIS IS A BIG OPPORTUNITY to maintain a character road," Wallwork began his presentation. He went on to compare the impacts predicted for traditional and nontraditional approaches.

The traditional method, consisting primarily of adding lights and turning lanes, he said, would accommodate a slight increase in traffic and would create a more efficient intersection at Crowell Road. However, said Wallwork, most other intersections would continue to cause long waits, and adding turning lanes would leave pedestrians with longer crossings.

The future efficiency of an intersection, given various treatments, can be calculated by a computer program called SIDRA (Signalized Intersection Design and Research Aid), he later explained. To add turning lanes, "a fair amount of right-of-way is required," he said, also pointing out, "Putting in signals won't necessarily reduce crashes."

Most of the crashes on Hunter Mill Road occur at intersections with traffic lights. Alternatively, the use of traffic calming measures is predicted to reduce wait time as well as reduce accidents at intersections and also allow a smoother, slower flow of traffic while making it easier for residents living on side streets to turn onto Hunter Mill, said Wallwork.

And when he says traffic calming, in this instance, he primarily means roundabouts, consisting of a circular island at the center of an intersection, around which traffic flows counterclockwise. Of the half-dozen traffic calming treatments appropriate for such a busy road, "the roundabout is best," he said. The reason is that they deflect traffic further out of its path than any other method, thereby slowing it down.

"If we do not deflect vehicles, we will not change driver behavior," he read from a slide. "Typically," he said, "we design roundabouts so that, going through them, you go about 15 to 20 miles per hour." Traffic flows more smoothly because, rather than stopping for a light, drivers yield to traffic in the roundabout, and accidents are less frequent because traffic moves in only one direction. It is easier to access the road from a side street through a roundabout because all turns are right turns, and it is easier to cross on foot because the pedestrian crosses only one direction of traffic at a time.

According to statistics from the Insurance Institute for Highway Safety, the addition of a roundabout reduces the crash rate at an intersection by about 40 percent and reduces the rate of serious crashes — the sort that cause injury — by about 80 percent.

At this point, Wallwork would recommend adding about 16 roundabouts along the length of Hunter Mill Road. Two of these would be at the interchange with the Dulles Toll Road, which he said would keep the interchange functioning at a high level of service into the future without having to widen the bridge. He also is recommending medians from Chain Bridge Road to the area of the Mystic Meadow Way intersection, at the W&OD Trail crossing, from Clovermeadow Drive to Crowell Road, at the sharp curve south of Mt. Sunapee Road, and from Cobble Mill Road to Baron Cameron Avenue.

He is suggesting the one-lane bridge on the northern stretch of the road be widened to two lanes, with a separate pedestrian bridge next to it and a trail running underneath it. However, he and Gibb, as well as Tom Flynn of Draper Aden, are quick to note that these are only preliminary suggestions, and any change would be gradual.

"Even though this may look like a commercial for one approach or another, that's not what we're doing here," said Gibb. "We want to hear from you." At this point, hands went up and stayed up.

"DURING RUSH HOUR, you cannot get out from Hunter Station," said Mike Martinka, asking how a median would remedy the traffic situation at the intersection, which is adjacent to the intersection with the W&OD Trail.

"If you prefer a roundabout, I can tell you it would slow traffic far more effectively," said Wallwork, noting that a median would cost less.

Evan Carb was concerned that trees suggested for the roadsides and median at that intersection might interfere with drivers' ability to see pedestrians. Wallwork agreed that the trees, which are intended to provide a visual cue for drivers to slow down, could not be too wide or too close together.

"Once we move everything quicker just to get down to [Route] 123, we're going to get stopped again. What are we going to do there?" asked Mary Schaeffer, who lives on the south end of Hunter Mill. "We'll be blocked completely."

She was one of a few residents who raised this concern. Wallwork responded that his solutions were for dealing with traffic on Hunter Mill itself and could not solve the problem of traffic volume. "It's do something or do nothing," he said. "The only way to fix Chain Bridge is to make it six lanes," he later said, adding that the cost of such a project and its impact on surrounding businesses would likely keep that from ever happening. "Whatever you do at Baron Cameron or Chain Bridge is not traffic calming. It's major interchanges."

Asked how much area a roundabout covers, Wallwork said an average diameter is about 130 feet. He noted that this often requires gaining some right-of-way, although generally not as much as is needed to add turning lanes at an intersection. Barbara Gahagan pointed out that Abbotsford Road had been planned to extend from Hunter Mill Road to Beulah. She suggested that opening up Abbotsford would help deal with the problem of traffic volume on Hunter Mill.

However, Wallwork noted that this was beyond the scope of the current study.

Roz Jones was one of several residents who worried that a steady flow of traffic, unbroken by stoplights, would make it more difficult to access the road from a side street that does not have a roundabout.

Resident Janet Methvin explained that traffic coming from a street without a roundabout can effectively make a left turn by turning right and then circling the next roundabout. "We lived in England for two years, where there are roundabouts everywhere, and they're wonderful," she said.

Others were concerned that the next roundabout might be a long way off. "If we go forward with this thing," reminded Gibb, "you might see one or two just to see if it works." Wallwork has suggested that an appropriate place for the first roundabout might be at the intersection with Mystic Meadow Way, where the entrance to the upcoming Oakton Park will be.

At this point, Wallwork later said, the stage of data collection and gathering input is more or less complete. "There's been a lot of input over the years," he said. The study is now in the process of being written, incorporating comments and concerns from Wednesday's meeting, as well as a meeting earlier in May with local officials and Virginia Department of Transportation representatives. The final draft of the study is expected to be completed by September.