There are lots of feats of engineering in the interstate interchange world. Everything from cloverleafs to roundabouts and now diverging diamond interchanges have been used. The purpose of all of these is to move traffic efficiently and with as many free flowing turns (no crossing traffic to turn left) as possible.
The video below clearly explains the purpose and uses for diverging diamond interchanges. You may recognize this as the interchange at the Hwy 6 I-70 interchange. When you enter this interchange your lane of traffic briefly shifts to the left side of the road. As does the traffic on the other side. This allows traffic entering from I-70 to turn left without having to cross lanes of traffic. Diverging diamonds don’t require an increase in traffic signals or lanes of traffic. Though they sound a bit scary at first, if you simply follow your lane you’ll be back on the “right” side of the road in mere seconds. For another great video, check out this animated one from the Utah Department of Transportation.
Still confused about roundabouts? We’ve got a blog post for that too! Both roundabouts and diamond interchanges are intended to make our roads safer for all who travel.