Let's Go Faster
There's one of those digital signs near where I live that tells you how fast your going as you approach it. You know the ones, with like, "Speed Limit: 50km/h" and "Your Speed: XX", with your speed where the X's are? When I pass it, it always tells me I'm going a lot slower than I think I am. So when my speedometer says I'm doing about 60 km/h, the sign says "52" or something. And it only flashes when you go above 55.*
So therefore, by my reasoning, the sign seems to be telling me that it's ok to do 60. Am I wrong?
*I can also make the sign flash "69" whenever I want. But I probably shouldn't share that with the entire world.
(posts)
4.21-en
Geek Support, fixing of bugger-ups, moral support, code splicing, tech. administration, whining, über-nerdery and fetching of fluffy coffees by 
Comments
If you are speeding but so is everyone else, will they still pull you over? This is a question that I ask myself every morning while on the dual carraigeway on the way to work, I try to keep beside someone who's at the same speed as me, they're not going to chase both of us...are they? (The speed limit is 60kmph, this I do not understand, as its 80kmph on the country back roads)
Posted by: Babs | May 19, 2006 8:37 AM
Those electronic signs are handy; it's nice to know how much your speedometer is overstating your speed.
Posted by: QE | May 19, 2006 10:46 AM
Babs - "Everyone else was doing it too" is not going to work as a defense if you are the one the Guards pull! :-)
Matt, speedometres are generally underclocked by the manufacturers by 5-10%. So when it says 100km/hour you are probably only doing 95.
This gives them a margin of safety in case of any legal action, and as over time they may drift out of calibration. Your situation of being overclocked is unusual.
Posted by: sliabh | May 19, 2006 10:53 AM
I wasnt going to use it as an excuse, see there is always someone else going way faster than me (I drive a 1L VW Polo, most of the people where I live drive massive cars, like Mercs, BMW, Porches, Bentleys etc, they can go WAY faster than me) so I think that the cops would pull them quicker than me you know?
Also, I have never seen cops there, ever, in the morning or evening, and I know where thay would be as well, so I am always at the speed limit there!
Are you a Speedometer geek Sliabh? I am worried that you know so much about them!
Posted by: Babs | May 19, 2006 11:51 AM
I am an Engineer. We know EVERYTHING....
(and I have a few friends that work in the car manufacturing industry)
Posted by: sliabh | May 19, 2006 12:51 PM
Actually I saw an episode of Top Gear all about this, and what you say isn't entirely true.
Analog speedos are generally accurate at 30-40km/h. They show a lower speed at speeds less than that (ie lower than actual speed) and a higher speed at speeds greater than that (again, higher than actual speed).
Digital speedos are generally accurate across all speeds, slightly underclocked.
Posted by: Matt | May 19, 2006 1:55 PM
I'm with you Matt. My understanding is that the faster you go the more innacuracy in the speedo (ie. the more MPH it will register below what you are actually doing.
So my reasoning is thus: If you are willing to do 80mph in a 60mph zone, then you have to realize that my going faster you're actually going even slower than you think you're going and therefor you should actually be driving at around 88mph. This reasoning is bulletproof. I've never had a fine in my life. I do however have an uncanny ability to both static camera's as well as the cops (especially when they insist on hiding on bridges over motorways and aiming laser guns at me!)
Posted by: Ian | May 19, 2006 6:53 PM