No longer assigned; renumbered in its entirety as I-395.

The Route 52 number was applied Sept. 15, 1964 to two sections of highway that had not previously been numbered: a segment of the Connecticut Turnpike from Waterford to the US 6 cutoff (SR 695), and a segment of "relocated Route 12" extending north to Route 101. "Relocated Route 12" was more of a planning number for the non-turnpike section, since there isn't evidence of it having been signed Route 12.

Route 52 becomes an Interstate

The idea of designating Route 52 as an interstate highway dates to the early 1970s. What spurred this idea forward in Connecticut, however, was Rhode Island's cancellation of its portion of I-84 in 1982. Connecticut decided to still extend I-84 anyway, to end at Route 52 in Killingly. If Route 52 were another interstate highway, state officials reasoned that getting federal approval and funding for I-84 would be easier.

In late 1982, Gov. William O'Neill asked the U.S. Transportation Secretary to consider an interstate designation, calling the route a "logical addition" as it links I-90 and I-95. Route 52 already met the physical standards of an interstate highway -- the other main criterion for acceptance.

For a while, it appeared Route 52 would become an extension of I-290 leading south from Massachusetts. A Hartford Courant article using the I-290 designation appeared just six days before the state announced, on June 20, 1983, that Route 52 was promoted to I-395.

Route 52/I-395 plays a part in the aftermath of the cancelled I-84 to Providence, plans to address tourist and casino traffic, and even the southern terminus of the long-awaited Route 11. There's more information at the I-395 page.