JoshBryan/ShutterstockThe 1970s marked one of the most significant transitory periods in American automotive history. Whether it's as mundane as the changeover from gross horsepower rating to SAE Net horsepower in 1972, to the 1973 and 1979 Oil Crises massively inflating gas prices nationwide, the entire industry changed dramatically within the span of less than a decade. Among all those changes, however, came new safety regulations mandating rollover protections, which ended the classic convertible – or so the thinking goes. While it's true that the government proposed new rollover protection standards in 1971, the decline of the convertible began several years before that in the 1960s, largely due to customer demand more than anything.That comes with several reasons and caveats of its own — namely, we're talking about the 1960s here. These aren't modern cars with modern weather stripping and climate control. Even cars like the original MX-5 are well-known to have leaky roofs, much less something from 60 years ago. Plus, climate control was either nonexistent or in a primitive format. A convertible top, by contrast, was a perfectly viable means of avoiding being boiled inside a black leather cabin in the summer. But as air conditioning became more prevalent and effective, with over half of new cars featuring A/C by 1969, the convertible top quickly fell out of fashion.Vehicles also received sunroofs en masse by the late-1960s, leaving a lasting impact along with the targa top. By 1976, Cadillac rolled the "last convertible" off an American production line, the Eldorado. Of course, it wasn't the actual last American convertible, but that was the sentiment at the time, as seen in its advertising campaign. So let's explore just how this phenomenon came about to begin with, and what caused the supposed "death" of the convertible in the 1970s.New options for a new era in automotive designDeepblue4you/Getty ImagesThree major changes in automotive design contributed to the downfall of the American convertible: climate control, the sunroof, and targa top. To begin with, let's look at the rise of air conditioning. Like most emerging technologies, original factory air wasn't exactly world-class. Original A/C, called "car coolers," looked more like a jet engine bolted to the passenger-side and used a water tank to cool the cabin. By the 1950s and early 1960s, technological improvements led to the popularization of the cabin air we know today. The AMC Ambassador became the first American car with an air conditioner as standard equipment in 1968, solidifying its place within the standard automobile.Concurrently, Ford pioneered the popularization of the sunroof with the debut of the 1960 Thunderbird. Its advertising emphasized the effectiveness of the sunroof as a climate control tool, which combined the benefits of a hard-top with those of open-air motoring. By 1967, the Thunderbird didn't even have a convertible body option and instead continued the sunroof trend with its steel-framed units manufactured by the American Sunroof Company. Other manufacturers followed similar lines by popularizing the vinyl roof cover, a covering for the car's hardtop that mimicked the look of a convertible.These concerns also led to Porsche introducing the targa top in 1965, featuring a prominent roll hoop over the cabin to improve safety. Other manufacturers followed suit, copying the aesthetic well into the 1970s with popular sports cars like the 1968 Shelby Mustang – which helped shape Carroll Shelby's legacy – and C3 Chevrolet Corvette gaining optional roll hoops and T-tops, themselves. These offered all the benefits of a convertible with the (theoretical) safety of a hardtop, the best of both worlds for consumers.
