National Maximum Speed Law for the 55 mph speed limit offered, "Speed limit 55. It's not just a good idea. It's the law.". Intelligentsia riffed that with a more absolute statement based on the speed of light: "186,000 miles per second. It's not just a good idea, it's the law." National Maximum Speed Law The National Maximum Speed Law (NMSL) in the United States was a provision of the Federal 1974 Emergency Highway Energy Conservation Act that prohibited speed limits higher than . It was drafted in response to oil price spikes and supply disruptions during the 1973 oil crisis. While Federal officials hoped
Variable speed of light While the measured value was later provided by Eddington in 1919, Albert Einstein went through several versions of light speed theory between 1905 and 1915, eventually concluding that light speed is constant when gravity does not have to be considered but that the speed of light cannot be constant in a gravitational field with variable strength. In the same book Einstein explained that he intended light speed to be a vector when it was described by coordinates in a reference frame. Einstein was not explicit about whether the speed of light would change in a gravity field, or whether just