Get rid of a lane and traffic flow will improve. You don't hear those words very often. But in the case of the SR 202 roundabout at the eastbound I-90 ramps in North Bend, less is better.
We installed a two-lane roundabout at the interchange in October 2007. While it has allowed traffic to flow more smoothly compared to the original stop-controlled intersection, drivers entering the roundabout from SR 202 in North Bend tend to use the wrong lane within the roundabout and cause confusion for others. To make the roundabout easier to navigate and reduce the risk of collisions, we will be reducing the two-lane roundabout down to one lane along three-fourths of the circle from southbound SR 202 to the eastbound I-90 on-ramp.
|SR 202/I-90 roundabout - existing striping|
A single-lane roundabout is pretty basic. Slow down as you approach, yield to vehicles already circling before entering, and then drive counterclockwise to your exit. A double-lane roundabout works the same, except drivers must choose a lane as they approach depending on where they are heading, and then yield to two lanes of traffic in the circle before entering.
After the roundabout opened to traffic, we observed a large percentage of drivers making wrong lane choices, especially those entering from southbound SR 202. So we wished to simplify the driver's task. In 2011, we reduced the number of lanes entering the roundabout from that direction from two to one. This lane reduction was our first step in simplifying and scaling back the original two-lane roundabout complexity.
That restriping project improved operations at the roundabout, but still allowed southbound SR 202 drivers the freedom to choose a lane once they entered the circle. In our recent observations, almost 60 percent of drivers are using the wrong lane when exiting the roundabout to the eastbound I-90 on-ramp. The drivers are circulating in the inner (left) lane. Then as they leave the roundabout, cross the path of those in the right circulating lane – a roundabout no-no. Drivers should choose the correct lane upon entering a roundabout and stay committed to that lane until they leave the roundabout. The observed crossover-error causes driver confusion and increases the potential for collisions.
Many of you have shared your concerns and suggestions about the situation – from colorful pavement markings to added signage for those who don't use this roundabout regularly. In the end, we decided getting rid of a lane within the circle would help clear up confusion for all drivers. Just like the last time we removed a lane here, our recent vehicle counts and traffic analysis for future volumes show one lane will be able to handle traffic at the interchange without added congestion.
|SR 202/I-90 roundabout - new striping|
Work on this low-cost project is scheduled to take place from 9 a.m. to 3 p.m. Wednesday, May 11. Drivers can expect single-lane and shoulder closures within the roundabout, with minimal delays. The new striping will use thermoplastic pavement markings, a much longer lasting and durable pavement marking material than paint.
Also proven – roundabouts reduce collisions and provide a safer way for pedestrians and bicyclists to navigate traffic. And that's why we've been adding more and more of them and some of you may have even noticed them popping up all across the country. In this case, more is better.