Your Speedometer Is Lying to You, and It's Completely Legal

Open a GPS app on your next drive and compare it with your dashboard. On most modern cars, the two numbers won't match, and the dashboard is usually the one showing more. That gap is not a fault. Under UN Regulation 39, followed across Europe and many other countries, a speedometer is never allowed to show less than your real speed, but it may legally read up to 10 percent plus 4 km/h too high. Carmakers build in that margin on purpose, because tire wear, tire pressure, and wheel size all change what the needle shows. The story gets stranger in America. After the 55 mph national speed limit arrived in 1974, federal regulators required new cars to use speedometers that stopped at 85 mph, with 55 highlighted on the dial. Owners of fast cars watched the needle hit the end of the scale while the car kept pulling, and the rule was dropped only a few years later. From there, we follow the numbers to today: why an ordinary family car can show 160 mph on its dial, how German and Japanese carmakers quietly agreed to cap their own cars, and a two-minute test you can do with your phone to find out how far your own speedometer is off. US Law Standardized Headlights Until 1983 : https://youtu.be/ubIwaWvdXIA Why Americans Drive Big Cars : https://youtu.be/F8Zf7E8W5vM #Speedometer #CarFacts #DrivingTips