that nobody ever cared to ask
Steve Whalen Boulevard (I'll abbreviate it as SWB from now on) stretches from an at-grade intersection from Hamilton Avenue on the north to a signalled at-grade intersection with Wyoming Street on the south, for a total length of about 0.5 miles. There is a large flyover/2 interchange with the US 35 freeway about 0.1 miles to the south of Hamilton Avenue. Known originally as the Hamilton-Wyoming Connector, it was renamed in the 1990's for a Dayton Police officer killed in the line of duty.
This highway is apparently the last remaining artifact of a planned north-south expressway across Dayton's east side. No expressway at this location exists on the 1962 master freeway plan for Dayton, so it was obviously planned and constructed later than that. The ramp configuration of the US 35 interchange suggests that priority was to be given to expressway traffic south of US 35. Based on this and what used to be located in Kettering a generation ago, the original target for SWB's south end could only have been the old Gentile Air Force Station (later the Defense Electronic Service Center). The only thing I have been able to find online that confirms this theory is a mention of a community effort in the Linden Heights neighborhood circa 1988 killing a high-speed six-lane extension to SWB. The Linden Heights neighborhood is south of US 35.
SWB's intended route north of US 35 has more data supporting its proposed location, but you have to do a little digging to find it. ODOT mandates that each district maintain something called a Functional Classification Listing, which describes in somewhat excruciating detail each highway the district is asked to maintain. Of particular interest for the District 7 listing on Montgomery County is the path taken by County Road 601. CR 601 is defined as Stanley Avenue from Keowee Street to OH 4, Findlay Street from there to 3rd street -- and Steve Whalen Boulevard. The apparent intent was to connect the current north end of SWB to the intersection of 3rd and Findlay, then widen Findlay from 2 to 4+lanes to OH 4 and Stanley Avenue (which is already 4 lanes from there north and west to I-75). Had the Findlay Avenue stretch been built, it would have completed a decent medium-speed collector road that would have taken some local traffic off of the downtown exits for both I-75 and US 35.
Both of these theories agree with my wife's memory of local politics in the 1970's. If I can locate planning maps and more history, I'll make it available here.