1915: Bissonnet started at Montrose Blvd. and headed west until it curved to the SW around “Poor Farm.”

1935: Same as above, but no name for the acreage out there.

1955: This maps show Bissonnet starting at Graustark and heading west until Edloe, where it changes to Richmond Rd.

1965: Bissonet runs from S Main to “Stafford Riceville School Rd.” which is present day Gessner. West of Gessner it’s Richmond Rd.

1967: entirely Bissonnet

1961 map showing beginning of Southwest Freeway, with Richmond Rd both in Bellaire and to the west.

1965 map showing Southwest Freeway completed down to Sugar Land, intersecting US 90. Richmond Rd. has been renamed to Bissonnet Ave. inside Bellaire and Houston city limits, but is still Richmond Rd. to the west.

http://www.gshtx.org/en/photos/v/868
(Souperman comments, “To maybe help any searches and to give readers a better mental picture of things… according to pre-Southwest Freeway maps, Richmond Road is better known as Bissonnet today (as it was the road to/from Richmond) coming from the southwest into town until it reached just north of West University and veered northward to join where the current Richmond Avenue is. Bissonnet continued eastward from where Richmond Road branched north.”)
So it sounds like ‘they’ opted to rationalize the name grid by giving Edloe a continuous stretch including the N-S segment of Old Richmond; Bissonnet (name still uncharacterized) a continuous trend westward; and Richmond the capacity not to be odd running E-W parallel with Old Richmond.
http://rktoday.blogspot.com/20.....chive.html says that the name was Old Richmond into 1961 at least, and a first guess is that the impetus for the name change was either the Southwest Freeway’s completion through there in 1962 or Schnitzer’s beginning of Greenway Plaza soon thereafter.