Why is Albert Lea the control city on I-35?

[Molandfreak]

I get that it's the junction of I-35 and I-90, but by that logic, should Austin not be a control city for I-90? Owatonna has a larger population than Albert Lea and much more infrastructure along the freeway. I-35 also meets two U.S. highways (14 and 218) in Owatonna, where I-90 only meets one (218) in Austin. What was MN/DOT's logic behind this?

[NE2]

Because it's the junction of I-35 and I-90. Neither Austin nor Owatonna is the junction of two Interstates, hence they aren't control cities.

[Molandfreak]

Austin is a control city! http://goo.gl/maps/04bo5

[NE2]

Oh. The phrasing 'should x not be y' usually implies that x is not y and you're asking if it should be.

AASHTO doesn't list Austin, so maybe it was a recent change. (It's not one-off; I see it on the ramp from US 52.)

[hobsini2]

Austin is not a "primary" control city, it is a secondary one. Secondary control cities show up most often at a regular interchange (non Interstate to Interstate) instead of a major junction interchange. Think of it like how Janesville and Beloit are secondary to Chicago on I-90 Eastbound at the I-39/90/94/Wis 30 Badger Interchange or I-55 in Illinois heading north from St Louis. Springfield, Lincoln, Bloomington, and Joliet are all secondary to Chicago and they only show up as control cities at less important junctions.

[TheHighwayMan3561]

Maybe they just wanted to put something between Sioux Falls and La Crosse.

EDIT: Oops, misread title and posts and thought we were talking about I-90. Point still stands though, just swap MSP and DSM in for the I-90 controls I mentioned.

[The High Plains Traveler]

It's also the control city for I-90 east at Sioux Falls.