The Reason Boise’s “Flying Wye” Almost Didn’t Get Built Is Hillarious

You drive on it every day, but how much do you know about Boise's Flying Y? For starters, did you know that it's actually spelled "wye"?

What is the "Flying Wye"?

The Flying Wye is the interchange where I-84 runs east-west through Boise, and I-184 branches off from I-84 and heads northeast into downtown. The shape of where these two highways merge and split, with I-184 going one way and I-84 the other, forms a Y.

How long has the Wye been around?

The Wye has changed quite a bit over the years.  The original Wye opened in 1968 when I-184 was built, but back then, it was called I-180N, and it connected I-84 to Downtown Boise via Franklin. It was two levels, so some lanes had to exit the freeway and re-enter on ramps or on the frontage road. It had left-side ramps, so you would have to cross multiple lanes of traffic to make a turn, which kept traffic from flowing. As Boise grew and the Wye got increasingly congested, it became unsafe and needed to be redesigned.

When did Boise decide to upgrade the Wye?

Discussion of a new Wye began as early as 1978 when there were public hearings at Capital High School. By April of that year, the project was canceled as opponents called it a "California-style freeway that would be a 1950's solution to a 1990's problem."  Is there a more Boise reason than that?  Yes, the anti-California sentiment has been around for a long time.

By 1987, public opinion had changed, and the need for a redesign became clear. By 1988, construction on the connector began, and finally fully opened in 1992. But it didn't take long before this new design became outdated.

What other types of three-street intersections are there?

A few different types of intersection designs were considered. The Partial Cloverleaf is like a basic wye but with some loop ramps replaced by flyover ramps. The Diamond, two loop ramps forming a diamond shape, allow traffic from any road to reach each other without crossing paths. Finally, the Trumpet, which has two ramps for one turning movement, reduces the weaving that caused many problems on the original Wye.

When was Boise's "Flying Wye" built?

Eventually, city leaders decided on the Flying Wye concept, and construction of the $86 Million project began in February of 1999. It was completed in September 2004. When it was finally done, the new Wye had flyover ramps on a "stacked interchange." It was built with growth in mind.

With our rapid growth over the past five years, how long before this Flying Wye needs a new upgrade?