greggerypeccary wrote on Dec 31
st, 2013 at 9:11pm:
buzzanddidj wrote on Dec 31
st, 2013 at 9:06pm:
Armchair_Politician wrote on Dec 31
st, 2013 at 8:10pm:
A Townsville man has copped a $146 fine for driving 1km/h over the speed limit.
This is a reminder of WHY it is called a "LIMIT" - and not a "SERVING SUGGESTION"
Exactly.
People just don't seem to understand what the word "limit" means.
Yes they do. It all comes down to Central Limit Theorem.
First of all, it is the responsibility of all drivers to calibrate their speedometers.
Quote:However from 1 July 2006, newly introduced models of a vehicle available on the market must comply with ADR 18/03. Also, from 1 July 2007 any newly manufactured vehicle (excluding mopeds) must comply with this rule.
This new rule requires that the speedo must not indicate a speed less than the vehicle’s true speed or a speed greater than the vehicle’s true speed by an amount more than 10 percent plus 4 km/h. Significantly, this change means that speedos must always read 'safe', meaning that the vehicle's true speed must not be higher than the speed indicated by the speedo.
That is, at a true vehicle speed of 100km/h the speedo must read between 100km/h and 114km/h. An alternative way to look at it is; at an indicated speed of 100km/h, the vehicle's true speed must be between 87.3 km/h and 100km/h.
Significantly, this change means that speedos must always read ‘safe’, meaning that they are not permitted to read lower than the actual speed of the vehicle.
This of course assumes that your seat is adjustd properly to allow a properly adjusted speedometer for parallax and that you have recalibrated the speedo if you have changed the type of tyres on your vehicle.
Interestingly enough, I find that my car overestimates the speed, which is why I rely on the GPS. The GPS shows the reading to the nearest 1 km/hr (which means that the standard error is +/- 2 km/hr. For a properly calibrated analog speedometer with the original tyres fitted (no wear), seat adjusted correctly etc, the standard error is typically double that.
http://www.racq.com.au/motoring/cars/car_advice/car_fact_sheets/speedo_accuracy