Aging and undersized: The Meridian Road interchange was built in 1965; the Broadway Avenue and Gowen Road interchanges went up in 1969. When new, each could readily handle the less than 15,000 vehicles traveling daily over, under and on and off each interchange. Since then, those numbers have skyrocketed. About 128,000 vehicles pass under or through the Meridian interchange daily, Broadway gets about 70,000 daily and Gowen about 44,500. The Idaho Transportation Department has decided these interchanges are in need of a makeover.

When? Construction on all three projects is scheduled to start in early 2014 and be complete by fall 2015.

Two SPUIs and a diamond: The new Broadway and Meridian interchanges will be single-point urban interchanges (SPUI), which use one central signal to control all lanes. ITD used the SPUI design at the Vista and Ten Mile interchanges. The Gowen interchange will be a traditional diamond format. Longer, wider ramps will be built at all three interchanges along with curb, gutter, sidewalk and bike lanes. ITD also will add a third travel lane between Broadway and Gowen.

Paying for it: The total pricetag for the three interchanges and the widening is about $124 million. ITD is using $80 million in GARVEE bonds. Between 2006 and 2011, the Legislature authorized $857 million in Grant Anticipation Revenue Vehicle bonds to fund highway improvements. Low interest rates and construction bids enabled ITD to bond about $80 million less than anticipated, so it is using that bonding for the new projects.

What's next? In coming weeks, ITD will meet with property owners and businesses surrounding the interchanges to provide information, gather input and answer questions. This summer ITD will hold public meetings; later this year, it will identify and purchase needed land.