Here's Why Prius Drivers Drive Like That

Found this in a Fox News story about speedometer accuracy:


How accurate are speedometers?
Dan Edmunds, an automotive engineer and the director of vehicle testing at Edmunds.com, says that speedometers cannot have an error of more than 5 percent (typically expressed as plus/minus 2.5 percent relative to the actual speed) according to federal law.
"At 60 mph this means your speedometer should read no more than 1.5 mph higher or lower than your actual speed," Edmunds explains."
He goes on to talk about tire wear and pressure variances, etc. But according to Edmunds, the law does allow for the speedometer to read HIGH or LOW, as long as it is within 2.5% accurate.



Read more: http://www.foxnews.com/leisure/2012/05/11/how-fast-are-really-going-accuracy-speedometers/#ixzz2Msqupemz

 

Here in the UK I think it's indicated speed must not be more than 10% of the true speed plus 4 km/h so at +10% mine is within tolerance but ridiculous in my opinion.

 

I'm not sure. My daughter had her cruise set at 76 and didn't notice the speed limit dropped to 55 and she was given a ticket for 76 in a 55