On this day in 1972, the results of a two-year study conducted by the National Highway Traffic Administration of the U.S. Department of Transportation are released; the study concludes that 1960-63 Chevrolet Corvair models are at least as safe as comparable models of other cars sold in the same period, directly contradicting charges made by the leading consumer advocate Ralph Nader.

In his bestselling 1965 book “Unsafe at Any Speed: The Designed-In Dangers of the American Automobile,” Nader had dedicated an entire chapter, titled “The One-Car Accident,” to the Corvair. Upon its debut in 1960, the Corvair won Motor Trend’s “Car of the Year” honors and became an immediate sensation thanks to its innovative design and its lightweight, air-cooled, rear-mounted aluminum engine. However, its deficiencies–including its tendency to oversteer and spin out of control in the hands of the average driver–earned almost as much attention. After his niece was seriously injured in a Corvair, the general manager of General Motors himself threatened to resign if the car’s suspension was not redesigned (it was, in 1964). By the time the revamped Corvair was released in 1965, Nader had already published “Unsafe at Any Speed,” making 1960-63 Corvair models the target of his most outraged criticism. Sales of the Corvair swiftly dwindled, and GM withdrew the car from production in 1969.

At Nader’s own urging, the U.S. government began a comparative study of the 1963 Corvair with other comparable vehicles in September 1970. The other cars used were a 1967 Corvair (featuring the newly redesigned suspension), a 1962 Ford Falcon, a 1960 Plymouth Valiant, a 1962 Volkswagen and a 1963 Renault. Nader had specifically criticized the Corvair’s handling and stability, as well as its tendency to roll over during sharp turns. In the study’s results, released on July 20, 1972, the government stated, among other conclusions, that the Corvair’s handling in a sharp turn did not “result in abnormal potential for loss of control” and that the rollover rate for the Corvair was comparable to that of “other light domestic cars.”

According to The New York Times, Nader spoke out against the study, calling it “a shoddy, internally contradictory whitewash” and accusing the Highway Traffic Administration of using “biased testing procedures and model selection.” He argued against the use of only the 1963 Corvair in the tests, which he said was significantly different from the 1960-62 models–a charge that the government disputed, saying that the first significant changes to the Corvair were made in 1964. Three independent engineers certified the government’s findings, calling them “reasonable, appropriate and sound,” and General Motors issued a statement stating that the study “confirms our position on the handling and stability characteristics of these cars.”