Do you remember your first experience with a roundabout? Do you stop? Do you yield? Speed up? Slow down?
After rolling through a roundabout – or traffic circle – more than once, they get a little easier.
The Ada County Highway District’s (literal and figurative) roadmap includes nearly 200 roundabouts in future years.
Instead of a stop sign or traffic lights, roundabouts allow drivers to enter a circular roadway by yielding to traffic. Engineers tout a decrease in conflict points, slower speeds and even environmental benefits. The Insurance Institute for Highway Safety said roundabouts cut accidents by more than a third – with a 75% decrease in injury crashes, and a 90% cut in fatal crashes. The MythBusters even found cars move through an intersection faster with a roundabout.
The first significant roundabouts in the area actually popped up in Canyon County at Happy Valley Rd. and Amity Rd. in 2006. For now, the intersection treatments remain in limited areas, including the Barber Valley, two new circles near St. Luke’s and scattered around the county. ACHD’s highest-profile roundabout to date remade the complicated intersection of 36th St, Hill Rd. and Catalpa Dr. The so-called “dogbone” roundabout smoothed out the flow of traffic, cyclists and pedestrians in the area near Hillside Jr. High.
More to come
But you might see a lot more in the coming years. The highway district’s “Master Street Map” shows a total of 176 roundabouts in nearly every part of the area.
Natalie Shaver with ACHD cautions that doesn’t mean you’ll be going round and round at every intersection.
“This does not mean they will all be built,” she said. “These are just areas where they would work.”
The map shows possible new roundabouts along many routes that could see major expansion or rebuilding in future years. The southwest quadrant of the county, which currently has many farm roads could hold roundabouts every half mile or so. Roads like Cherry Ln. and Franklin Rd. could add multi-lane roundabouts in areas that will soon interface with the State of Idaho’s freeway-like Central Valley Expressway project that would run north-to-south near the county line.
In ACHD’s next fiscal year, the traffic circles will pop up at Victory Rd. and Locust Grove Rd., Amity Rd. and Maple Grove Rd., Linder Rd. and Floating Feather Rd. and a few other locations. A so-called “mini-roundabout” is planned for Rose Hill St. at Owyhee St. as part of bikeway improvements on the Boise Bench.
Shaver said a total of 44 roundabouts are included in ACHD’s Capital Improvements Plan – which is a 20-year planning document for road improvements in the county.
Here’s a list of the roundabouts envisioned in the CIP (single-lane unless otherwise noted):
- Amity & Cloverdale – multi-lane
- Amity & Eagle – dual-lane
- Amity & Five Mile – multi-lane
- Amity & Linder
- Amity & Maple Grove
- Amity & Ten Mile
- Beacon Light & Ballantyne
- Beacon Light & Eagle – multi-lane
- Beacon Light & Linder – multi-lane
- Beacon Light & Palmer
- Beacon Light & Park
- Columbia & Cloverdale
- Columbia & Ten Mile
- Deer Flat & Ten Mile
- Floating Father & Ballantyne
- Floating Feather & Linder – multi-lane
- Floating Feather & Palmer
- Floating Feather & Park
- Floating Feather & Plummer
- Floating Feather & Star
- Franklin & McDermott
- Gowen & Orchard – multi-lane
- Hill & Horsehoe Bend – multi-lane
- Hill, Hill Parkway & Seaman Gulch
- Hubbard & Ten Mile
- Kuna & Cloverdale
- Lake Hazel & Black Cat
- Lake Hazel & Eisenman – dual-lane
- Lake Hazel & Five Mile – dual-lane
- Lake Hazel & Linder
- Lake Hazel & Locust Grove
- Lake Hazel & McDermott
- Hake Hazel & Orchard – dual-lane
- Lake Hazel & Pleasant Valley – dual-lane
- McMillan & Black Cat – multi-lane
- McMillan & Star – multi-lane
- Pleasant Valley & Orchard Extension- dual-lane
- Overland Rd. Extension & Black Cat
- Ustick & Black Cat – dual-lane
- Ustick & Star
- Victory & Black Cat
- Victory & Linder
- Victory & Locust Grove – multi-lane
- Victory & McDermott