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
Speed of light fibre optic signals which travel 30–40% slower at the speed of light through glass. There are different ways to determine the value of "c". One way is to measure the actual speed at which light waves propagate, which can be done in various astronomical and earth-based setups. However, it is also possible to determine "c" from other physical laws where it appears, for example, by determining the values of the electromagnetic constants "ε" and "μ" and using their relation to "c". Historically, the most accurate results have been obtained by separately determining the frequency and wavelength of a light beam,