May 8, 2008
State puts spin on roundabouts
by Brian Wilson
Roundabouts have arrived in Wisconsin and with the backing of national insurance groups and the state department of transportation, they aren't going to go away.
What this means for Medford residents is the planned reconstruction of portions of Hwy 13 through the city includes replacement of two existing intersections with the traffic circles. However, the transition from lines on a page to construction is still at least three years away and the plans are far from completed.
Up until about a month ago, planning for replacement of the intersection at Allman Street and Hwy 13 (Eighth Street) and Ann's Way and Hwy 13 were proceeding as normal with plans to replace the exiting signals with new signals and expanded turn lanes. In fact a public meeting on the project was held last year with preliminary plans showing the traditional signaled intersections. However, as DOT staff explained under a departmental policy all new or replacement intersection projects must look at including roundabouts in place of traditional controlled intersections.
Four staff members from the Wisconsin DOT were in Medford Monday morning to talk with The Star News editorial board about why they feel roundabouts are a good fit for the city. DOT personnel will meet with the Medford City Council on May 12 to discuss roundabouts and other Hwy 13 reconstruction issues.
There will be at least three other public input opportunities for people in the community to learn more about roundabouts and give input.
The DOT came in response to an editorial critical of the roundabouts planned for the city, and they noted that they were not surprised by the negative sentiment toward this new form of traffic control. According to a study by the Insurance Institute for Highway Safety, a majority of people either somewhat or strongly oppose roundabouts prior to construction, however that drops to 24 percent typically following construction.
According to the DOT, modern roundabouts are a new form of intersection in this country, but are based on years of study from other countries. The so-called modern roundabout was first developed in England in 1963 and according to the DOT is different from other circular traffic control devices that have been used.
According to Phil Keppers, a project manager for the Hwy 13 project, the following three basic principles set modern roundabouts apart from other traffic circles:
1. Yield-at-Entry — Vehicles approaching the circular intersection must wait for a gap in the circulating flow, or yield, before entering the circle.
2. Traffic Deflection — Traffic entering the roundabout is directed or channeled to the right with an appropriate curved path into the circulating roadway that avoids the central island.
3. Geometric Curvature — The radius of the circular road and the angles of entry can be designed to slow the speed of vehicles.
He explained that while on the surface, modern roundabouts and old traffic circles and rotaries look similar they differ in the design philosophy. Older traffic circles which are used primarily in the northeastern states were designed for higher speed travel while modern roundabouts are designed for low speed use. Keppers notes that many of those older traffic circles are being replaced with modern roundabouts.
In a roundabout, traffic entering the circular roadway yields to traffic already in the roundabout. The traffic then flows in a counterclockwise direction around a central island until it exits from the circle.
According to the DOT, the ability to slow traffic without stopping it as you would have at traffic signals is a major selling point. Keppers noted that Hwy 13 is a long-haul truck route and that the nearest traffic signals to the north are in Park Falls leaving a long stretch of open highway before traffic has to slow to enter Medford. He explained that a sudden stoplight at Ann’s Way can be missed, but that a roundabout by its design requires traffic to slow, without forcing it to come to a stop.
One aspect of roundabouts that Keppers noted was that the central island includes a paved, roll-up curb that truckers are supposed to drive onto in order to make the turning radius of the roundabout. When asked about the heavy logging traffic that goes through Medford and the potential for poorly secured logs spilling as the trailer tips, he replied that this was taken into account with the design of the intersections here and that they were drawn to be wider in order to accommodate the trucks not needing to go into the central island as much.
Safety was a major selling point for the DOT personnel, they note that a conventional intersection has 32 “points of conflict” with possibilities of merging, crossing and separating traffic. By comparison a roundabout has only eight conflict points and of those, there are no crossing points. Since traffic is moving in the same direction, the collisions that occur are typically less severe. According to the Insurance Institute for Highway Safety, crashes decrease by 39 percent when intersections are converted from conventional to roundabouts, with the rate of injuries decreasing 76 percent and fatalities decreasing by 90 percent because of the elimination of the possibility of T-bone collisions.
Roundabouts are a reality in Wisconsin, the DOT representatives say plans are to build 175 roundabouts in the state system. There are currently 16 roundabouts on the state system with seven of them single-lane and nine multi-lane, an additional 125 are proposed on state roads and there are 27 known roundabouts on local road systems.
With Wisconsin and other states jumping on the roundabout bandwagon, there will be a need for driver education as they become more popular.
One area that will require education is how to deal with emergency vehicles in the roundabouts. If a driver is in a roundabout and a fire engine or other emergency vehicle approaches, the driver should continue through the roundabout and pull over only after leaving the roundabout.
On the long-term maintenance side, roundabouts eliminate the need for traffic signals and maintenance of those signals. According to Keppers, while a roundabout is larger than a conventional intersection, it actually has less paved surface area.
While the DOT is confident that replacing the conventional intersections at Allman Street and Hwy 13 and Ann’s Way and Hwy 13 with roundabouts is the best thing today, there are still plenty of opportunities to change their mind. In addition, although this is a state project the local municipalities will have some input into how the intersections are rebuilt and if roundabouts are installed, since by law local municipalities pay a portion of the project costs.
