This might be the most obscure signed state highway in the Hartford area. It doesn't intersect the Berlin Turnpike (though it gets close); and the other major highway it intersects (Route 9) doesn't mention it by number.
The particulars of Route 174's original western end as of Jan. 1, 1932 are a bit murky. I don't have a 1932 highway log or a clear enough map. But the original western terminus appears to be East Street, which was part of Route 175 at the time. In Newington, the road used to cross Willard Avenue (Route 173) at a four-way intersection. Balducci Way is part of the original alignment.
In 1934, it was extended in New Britain along East Street (former SR 778) and probably along East Main Street to Stanley Street, which was Route 71 at the time. Now Route 174 was 2.88 miles long.
Route 174 was almost deleted from the state highway system in the state's Route Reclassification in 1962. The state wanted to turn it over to the towns, possibly because it paralleled Route 175, another state highway.
The city of New Britain insisted the state retain control, because of the road's "increasing importance in arterial traffic flow of the city." The state countered that Route 174 is a "short leg", and the traffic load was not as heavy as the city contended.
Route 174 even disappeared from a few state maps in the 1960s, which must have pleased city officials. However, it remains in the state highway system to this day, along with several other short leg routes in the area.
In 1976, Route 71 was moved from Stanley Street to South Main Street in New Britain, as a consequence of the new Route 72 freeway severing Stanley Street. Route 174 was extended a short distance west to the new Route 71, for a length of 3.06 miles.
In 1980, the DOT proposed an area road improvement program to be financed by trade-in funds from cancelling I-291 west of I-91. The improvements related to Route 174 would be:
Neither of those improvements took place.
In 1988, the state abandoned a plan to widen Route 174 to four lanes between Route 173 and Route 176.
In 1990, the state and town disagreed on what to do with the Route 173/174 intersection in Newington. The town wanted to create a dogleg (overlap 174 with 173 for a block or two) to unify Churchill Park, which current Route 174 passed through. The state preferred leaving the roads as is, and adding a traffic signal. Between 1996 and 1998, the town's plan was implemented. Now Route 173 and 174 are the only consecutively numbered routes that overlap.