southbound, approaching Route 68 in Wallingford. Photo taken April 2004 by Kurumi.
Commissioned in 1932 from the old State Highway 325, Route 68 originally existed only between Route 63 in Naugatuck and Route 70 in Cheshire. Two unsigned state roads, SR 730 (Church St) and SR 607 (Barnes Rd) continued through Wallingford to Durham.
Extension to Durham, and I-91
In 1964, possibly to give Yalesville and Durham better access to the planned I-91, Route 68 was extended over SR 730 and SR 607 to Route 17 in Durham. Signing changes appear to have taken place in 1966, when I-91 opened here.
The "Super 4" segment in Wallingford
In 1973 and 1974, Route 68 was relocated in Wallingford, leading to the 2.5-mile segment of four-lane, undivided, access controlled road (almost a Super 4). Several parts of the former Route 68 exist as Barnes Road, which the new highway parallels. The state labeled these parts as SR 752A in 1973, and turned them over to the city in 1974.
In Cheshire, Route 68 was straightened out west of where it crosses Broad Brook Reservoir in 1966. The original route followed a sharp curve north, closer to the shore.
Another realignment was done in Wallingford in 1968, but I have no details for it.
In 2002, a one-mile segment from Williams Road to Leigus Road was widened (mostly four lanes with turning lanes), and two side streets were made into cul-de-sacs to decrease the number of access points. This widening was first suggested in a 1988 study of Route 68 between Durham and Cheshire.
In 2004, the interchange with I-91 was slightly realigned, with the overpass widened to five lanes, to add left-turn lanes onto the entrance ramps. This was supposed to finish in fall 2003, but a structural problem, requiring redesign and reordering of bridge supports, delayed its completion.
The state once had grander plans for Route 68: a freeway, leading from a proposed Route 10 freeway in Cheshire across Wallingford into Durham. This was in the category of "proposed highways for future traffic needs", and was never constructed. In fact, I haven't seen evidence of any public hearings or detailed design for the Route 68 freeway itself.
This scan from the 1938 official state map shows the proposed trunk line route leading from Durham to Higganum in Haddam. The route follows Maiden Ln, Bear Rock Rd, Higganum Rd, and Candlewood Hill Rd.
Proposed Extension to Haddam
In 1935, the state assigned Route 180 to a proposed trunk line route from Durham to Haddam. The 1938 official state map shows the proposed route. Route 180 was never built; if it had been, it would be a natural extension of Route 68.
Proposed widening declined
In 1998, though congestion and a commercial boom in Wallingford had touched off calls to widen Route 68 near US 5, the state said it would not be widened in that area.