In the 1920s, State Highway 146 followed today's Route 195 between US 44 and Route 89.

The modern Route 146 was commissioned in 1932. Its original length was 8.04 miles, and followed this route, from west to east:

• Leetes Island Rd, from US 1 to Stony Creek Rd (this is now a town road)
• today's Route 146 to US 1

About 1.7 miles of the route, in Branford and Guilford, was maintained by the towns. The state took over maintenance here in 1955.

In 1962, it was extended westward to US 1A in Branford, taking over parts of Stony Creek Rd., Totoket Rd., and the former Route 143. The north-south segment of Leetes Island Road was turned over to the town of Branford. The Stony Creek Association in that town opposed the move, stating that the road (and Route 146) was the neighborhood's connection to the rest of the state. Route 146 was preserved (and extended) but the direct north-south connection is now a town road.

In 1963, US 1A was deleted in Branford, and Route 146 was extended further westward to US 1.

Turning things around, here's what each portion of today's Route 146 was designated originally:

• West Main St and Main St, Branford: US 1 until 1940; then US 1A until 1963
• South Main St, Branford: SR 445 from 1939 until 1962
• Montowese St through Elizabeth St, Branford: Route 143, until 1962
• Blackstone Ave, Totoket Rd and Stony Creek Rd: town roads until 1962
• the rest of Route 146 in Guilford is as original

Projects proposed but not (yet) implemented

Some of the features that make Route 146 one of the most scenic highways in the state also make it unsuitable for some vehicles, a liability in some environments, and vulnerable to the coastal climate. It crosses under the Shore Line East railroad four times, with clearances ranging from 13 feet 6 inches down to 8 feet 8 inches. Some parts are less than 10 feet above sea level and flood regularly. Some causeways and bridges do not meet modern standards for safety or construction, and do not allow proper waterflow to inland areas.

Though the state has proposed improvements to Route 146 over the years, it has been difficult to get general agreement and support from the community.

In 1967, the state proposed replacing the 9-foot-6-inch railway underpass on Montowese Street (see map) with a new bridge over the railroad (with clearance of probably 20 feet or more). This project would have realigned or rebuilt a significant stretch of Route 146. Hearings were held again in 1972, but no construction was done.

In 2019, the state held hearings about replacing a causeway and culvert at Great Harbor (see map). The culvert was built in 1930 and the culvert dates to the late 19th century. The state's proposal: a three-span, 360-foot bridge, with two 11-foot lanes, and two 5-foot shoulders for pedestrians and bikes. Work on the $14 million project would take about 18 months. The bridge would allow proper waterflow to inland areas, which the culvert does not. Local reaction was mixed; the new bridge "looks like a little piece of I-95 that’s fallen out of the sky," said a Guilford resident.

South Central RPA's "A1A" proposal

In 1967, the Regional Planning Agency of South Central Connecticut unveiled its Open Space 1966-2000 report, which included a proposal for a continuous shoreline road from Milford to Madison. It would not be right next to the shore at all points, but would offer better access than the series of small roads connecting to US 1 and other inland routes.

For Florida residents and visitors, the plan would resemble its A1A highway, which parallels US 1 closer to the beach and its neighborhoods. The proposal included some relocations to Route 146. I don't know what the completed shoreline route would have been called.