Question Of The Day: Why Did 1980s Cars Have 85-MPH Speedometers?

Question: Why did so many muscle cars in the 1980’s have speedometer that maxed out at 85 mph?

Answer: It wasn’t just muscle cars that had speedometers that could only go to 85 mph. Every vehicle manufactured and sold in the United States during the 1980s had a speed cap. No matter the car, the needle on the speedometer couldn’t be pegged any further right than 85 mph.

The reason for this had very little to do with speed, and everything to do with energy conservation, sparked by a shortage of oil in the 1970s.

In 1973, the Organization of Arab Petroleum Exporting Countries – OAPEC (every Arab member nation of the Organization of Petroleum Exporting Countries, or OPEC, plus Egypt and Syria) – began an oil embargo on every nation that supported Israel during the Yom Kippur War in October that year. One of those nations on the list was the United States. Fuel rationing, high fuel prices, energy conservation, and the search for alternative energy sources were some of the results of the oil embargo the following year.

Energy conservation, in particular, led to a few legislative actions which would affect the country, one of which was the 1974 Emergency Highway Energy Conservation Act. The act had a provision dubbed the National Maximum Speed Law (NMSL), which did away with speed limits set by state governments, replacing them with a national 55 mph limit. Before this legisation, speed limits were as high as 75 mph, with Montana and Nevada not having posted limits on rural roads.

The intent of NMSL was to conserve fuel use, based partly upon the belief being cars and trucks achieved their greatest fuel efficiencies between 40 and 55 mph. But its impact was minimal: Fuel consumption during the time the speed cap was in place fell just 0.2 percent and 1 percent, according to the U.S. Transportation Research Board.