I'm sorry, but that's not an expressway — it's a four-lane arterial. See the next comment.
To start with, US 71 is a good example of an expressway. For those that don't know, 71 is four-lane divided with a wide median and frontage (outer) roads where neccesary. The only difference between it and a freeway are the fact that a freeway has interchanges only — an expressway can have at-grade intersections. In fact, 71 could be improved to a freeway (and it will be eventually, as part of Interstate highway 49) by shutting down some of the crossings and/or separating them to make interchanges.
In order to imporve the existing roadbed to an expressway, simply adding two lanes to the existing two would not work because the idea does not change access patterns for the existing curb cuts. Without eliminating the curb cuts, 59 would become more of a game of Frogger than a safe road to drive on. To upgrade it to an expressway, the existing curb cuts would have to have frontage roads built to them. Generally, there's a 60 foot median between the frontage road and the main line. By the time you account for the second set of lanes, frontage roads (where neccesary) and setback requirments, most houses would have to be moved or bought out. This eliminates some curb cuts, as well as some frontage road, but is also nedelessly wasteful. Alternatively, the new roadway could be built parrallel to the exisitng road an retain the existing as a frontage road (as one of KDOT's proposals shows). This tends to be standard procedure for roads rebuilt to limited access in Kansas. However, this still requrires all the property along one side of the road.
So, why a freeway and not an expressway? It all boils down to wheather the intersections should be at grade or seperated. KDOT believes they should be seperated because they believe that the cross-traffic is heavy enough to pose a danger to through traffic. This isn't as big a problem on US 71, as cross traffic is lighter on the generally more rural corridor.
KDOT has also had bad expreiences with expressways near and between large urban areas. K-96, the inaptly named “State Fair Freeway” an US 75 just north of Topeka both contain at grade intersections that have had complaints on them becuase of the relatively large amounts of turning traffic.