Friday, January 15, 2021

Coming around to roundabouts on SR 99 in Fife

By Nick VinZant

What did the engineer say to the driver who was skeptical about roundabouts? "Give it some time and you'll come around."

Okay, maybe we won't make it on the comedy circuit anytime soon but stick around to learn about a new roundabout under construction in Fife. Northbound SR 99 traffic will start using it soon. As part of the SR 167 Completion Project, we are building a new roundabout to reduce congestion and improve freight mobility in the area. In fact, we worked with the City of Fife, the Port of Tacoma, and the freight community to make sure it can accommodate the large trucks that will use it regularly, as well as cars and people who walk and bike through the area.
Round and round we go. The SR 167 Completion Project includes a new SR 99 roundabout
and new, four-lane 70th Avenue East Bridge.

The roundabout
The new SR 99 roundabout will connect SR 99 and the new 70th Avenue East Bridge. Drivers will enter the roundabout from either SR 99 or 70th Avenue East and then travel in one of three directions: south on SR 99, north on SR 99 or south on 70th Avenue East. Like other high-volume roundabouts designed with trucks in mind, this roundabout has two lanes. It also has two bypass lanes: One that will provide direct access to 70th Avenue East from northbound SR 99 and one that will provide direct access from 70th Avenue East to northbound SR 99. In addition to two through-lanes, the new SR 99 roundabout will have sidewalks and crosswalks for people who bike and walk in the area. The crosswalks include pedestrian-activated flashing beacons.
The northbound portion of the roundabout is nearing completion. Northbound traffic (highlighted in green) will start using the roundabout soon. Southbound traffic (highlighted in blue) will shift later in the year when construction is finished.

Opening act: Half a roundabout
We've been busy building the northbound lanes of the roundabout next to SR 99. As early as January 30 (weather permitting), we will shift northbound traffic into the roundabout and crews will start working on the southbound lanes. Think of it as our opening act. Southbound SR 99 drivers will continue to use the current southbound SR 99 alignment until all construction is done, with both directions expected to be fully open by mid-2021.

Why a roundabout?
Yes, they take some getting used to. But ultimately, roundabouts help traffic flow better (no stoplights), are safer (reduced speeds), and are more cost efficient than intersections using traffic signals. How do we know?
  • Improved traffic flow: A recent study out of Kansas State University shows that there's a 20 percent reduction in delays when roundabouts are used instead of stoplights. A second study by the Institute for Highway Safety (IIHS) concluded that roundabouts reduced vehicle stops by 56 percent. These types of reductions are especially important at intersections like SR 99/70th Avenue East, where there's a large amount of freight traffic. We worked closely with the Port of Tacoma and the freight community to ensure the roundabout will work for large trucks. For example, this roundabout is designed with wide lanes and what's called a truck apron (a sloped, raised section of pavement around the center island) that trucks can easily drive over and complete their turns.
  • Safer: Studies also show roundabouts reduce injury collisions. According to the IIHS, roundabouts reduce fatal crashes by 90 percent, injury crashes by 75 percent and overall crashes by 37 percent. Because of their design, roundabouts greatly reduce the dangerous T-bone collisions that can occur at signalized intersections.
  • More cost-efficient: Traffic lights are expensive. On average, they cost between $5,000 and $10,000 a year to maintain. The new roundabout provides a cost-effective, safe traffic solution.
The bigger picture
We designed the new roundabout to work with the rest of the 70th Avenue East Bridge Replacement Project – a new bridge over I-5 at 70th Avenue East. The bridge replaces an existing two-lane bridge with a four-lane bridge and adds a 12-foot-wide shared used path. The bridge and roundabout will reduce the delays drivers currently experience on the existing bridge and SR 99/70th Avenue East intersection, as well as improve safety for everyone who drives, walks, bikes or rolls through the area.

Wait, wait. We've got one more…
What do you call happy drivers in a roundabout? A Merry-Go-Round! If that doesn't get you in the mood to drive in the new roundabout, we have some excellent resources you can circle back to. Below you will find everything from safety tips to an instructional video.

2 comments:

Unknown said...

Turns are to tight for semis bad enough for cars. Going to slow 99 down badly. Will be lots of traffic jams

Unknown said...

I agree the roundabout is too small. There are now signs saying not to drive next to the semi trucks. I have touched my tires on my KIA soul. Why is this intersection so tight when it's main reason for existence to relieve truck congestion on 70th st.

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