Roundabout round table

By William Rohrs Staff Writer, Healdsburg Tribune

Merry-go-round
Merry-go-round
Dispelling myths about the solution to Healdsburg’s five-way intersection

Concerns whether emergency vehicles and large trucks could cross Healdsburg’s proposed roundabout came full circle when Urbangreen founder Jim Heid and GHC consultant Frank Penry shattered myths about roundabout safety and design. Not only are roundabouts a safer alternative to the current five-way intersection on Healdsburg Avenue and Mill Street, the community welcomed an opportunity to move all their utility lines in the area underground, cleaning up the aesthetic of Healdsburg busiest traffic area.

Heid said a roundabout wasn’t a new idea. Rather, a Regional Urban Design Assistant Team (RUDAT) study conducted in 1982 suggested a roundabout would better replace the original five-way intersection. Healdsburg conducted the RUDAT study to plan for future growth scenarios. “There’s been about a decade of progress and reasearch that’s led to this conclusion,” Heid said.

The Oct. 28 workshop focused on the creation of a roundabout, but the whole plan includes improvements to roads beyond Healdsburg Avenue and Mill Street The scope of the project comprises of five parts, which include improvements to Healdsburg Avenue, upgrading and safety improvements to the five-way intersection and the reconstruction of Foss Creek, among other municipal projects.

Penry led the discussion to dispel myths surrounding roundabouts. He focused on various traffic safety statistics and simulations conducted in 2001 by the Insurance Institute for Highway Safety. “Fatality collisions were reduced by 90 percent after roundabouts were installed at an intersection,” Penry said. “Driver sight lines are directed toward pedestrians. They can see you coming, you can see them coming.”

Penry’s first myth revolved around the belief that a roundabout, traffic circle and rotary are synonymous. “Traffic circles like the ones around London and Eastern Europe are large, multi-lane circles that have a lot of movement,” Penry said. Rotaries on the east coast envelop large areas of land and block line of sight from one side to the other. The proposed roundabout for Healdsburg consists of a single lane circle with five “legs” where traffic enters and exits at 15 mph, with rail signs for the train to pass through. Penry said the slower speed helps create more opportunity for entering and exiting the roundabout. He provided a simulation where the train enters the roundabout, forming a queue that slowly builds through the train’s transition, but clears quickly after the train makes its way out.

The community’s biggest concern is the myth that a roundabout cannot host large trucks or emergency vehicles. “That’s not true,” Penry said. “In fact, large vehicles are a big part of the design in roundabouts.” He then played a simulation where a large vehicle could use a “truck apron,” a slightly raised surface in the middle of the roundabout, to navigate around and exit without incident. Truck aprons are typically made of different materials from the road and are raised in order to discourage drivers from abusing them.

Penry showed a side-by-side comparison of the possible collision points in the current 5-way intersection and the proposed roundabout. The current intersection has 24 points where collisions are possible. Due to the roundabout’s circular nature, the collision points are reduced to eight. “Because the cars are going at 15 mph, the nature of the collisions are much lighter,” Penry said.

To discourage pedestrians from walking directly into the roundabout, Heid proposed a vista in the center designed to be unreachable from the outside of the roundabout. “It’s very important to have a vista so people don’t believe they can drive over it,” he said. The roundabout is projected to accommodate Healdsburg’s traffic needs for the next 30 years.

Heid scheduled the next workshop for Dec. 3, where the community can directly voice their input for the roundabout’s design and character elements, like placing all the currently aboveground utility lines underground. Without another World Series game, Heid is confident attendance will be much higher for the next workshop.