Designed for Connecticut's Gold Coast, the parkway is known for its scenic layout, its uniquely styled signage, and the architecturally elaborate overpasses along the route.

Facing bitter opposition, the project took six years to build in three different sections, with the Connecticut Department of Transportation constantly requiring additional funding due to the area's high property value.

The roadway sign of the Merritt features a blue shield with white lettering, along with the foliage of Kalmia latifolia, commonly known as the mountain laurel, the state flower of Connecticut.

[11] Vehicles 8 feet (2.4 m) tall or taller in height, weighing 8,000 pounds (3,600 kg) or more, towing a trailer, or having more than four wheels are not allowed on the parkway.

Built between 1934 and 1940, the Merritt Parkway runs for 37 miles (60 km) from the New York state line in Greenwich to the Housatonic River in Stratford.

[17] To ease objections from county residents, who feared an influx of New Yorkers on their roads, in their towns, on their beaches, and through their forests, highway planners called on engineers, landscape architects, and architects to create a safe and aesthetically pleasing limited-access highway, one with exit and entrance ramps, but no intersections, that would not spoil the countryside.

[23] In 1955, exit 30, an at-grade intersection with Butternut hollow road that crossed traffic in both directions, was permanently closed.

[23] In April 2001, a complete reissuance of the parkway's signs was carried out, instituting a uniform white-on-green color scheme and a sawtooth border.

[23] After years of environmental studies, the Connecticut Department of Transportation awarded an $87 million contract to Balfour Beatty Construction to build the replacement Igor I. Sikorsky Memorial Bridge in 2000.

[31][32][33] The new bridge has a concrete deck, with an asphalt surface, three lanes in each direction, full left and right shoulders, a sidewalk for pedestrians, wrought-iron railing, and aesthetic lighting.

[34] Six rest areas/service plazas, featuring parking lots, gas stations, and convenience stores, were also built along the Merritt Parkway so that drivers would not have to exit to refuel.

[citation needed] In 2013, electric-vehicle (EV) charging stations for Tesla automobiles were added to both the northbound and southbound Greenwich service plazas, with four Superchargers installed in each direction.

Trees that line either side of the parkway, and often in the center median, grow branches that cover the roadway, and occasionally fall during severe weather, or with natural aging.

Stretches of the parkway also lack guardrails on the right shoulders, creating a risk of tree-impact accidents if cars veer off the pavement.

In 2007, after complaints were voiced about the danger of the trees along the parkway, state officials announced they would trim and eliminate some of them more aggressively.

A large, seemingly healthy tree fell on a car near exit 42 in Westport in June 2007, killing a couple from Pelham, New York.

The state Department of Transportation commonly sends out work crews twice a year to drive along both sides of the parkway at 5 miles per hour (8.0 km/h) in search of decrepit trees.

After Sandy, the state began a large effort to remove unhealthy trees, and in the process created much wider clearances between the roadside and forest.

[36] In addition to numerous trees along the Parkway, interchanges were originally designed with Right-in/right-out (RIRO) ramps with no acceleration or deceleration lanes.