How many of you still see a 55 mph speed limit on 4-lane highways? Back in 1974, as part of the Emergency Highway Energy Conservation Act, states had to agree to the limit maximum speeds to 55 mph, on all 4-lane divided highways, if they desired to receive federal funding for highway repair. Incredibly, after almost 50 years, in NJ, there is one stretch of Route 42 that still has this ridiculously low speed limit. However, just like in Prohibition, where the public did not support the Federal law, everyone here disregards it.
Speed is only one aspect of fuel economy. The Govt set the speed limit at 55 to save fuel, but my 340 Barracuda always got better fuel efficiency at 65 and not 55. I wonder how many other vehicles behave similarly. I know that wind resistance goes up as the 4th power of speed, but the difference between 55 and 65 is still small and wind resistance is only one factor. Leave it to the government to make decisions that "benefit all of us!" in their infinite wisdom (or more likely bowing to special interest groups.)
