Caught Speeding- Blame your tyres!
It took a change of government in N.S.W. apparently, to inject some commonsense into the setting of limits for “overs” on fixed and mobile speed cameras.
The Roads and Traffic Authority had decreed that henceforth the limit would be 2%. The first act of the Minister-Elect was to decree that this wouldn’t happen. The police weighed in with the comment that a thick speedo needle, or fitting a new set of tyres, could cause an error bigger than 2%. You know what- the police were right! Incidentally, in Victoria it’s 2% for fixed cameras, and 3% for mobile cameras. What the basis is for this difference is unknown.
But both police forces admit that there is a “discretionary factor”. This was once explained to me as “the cost of the paperwork and time may make it not worthwhile for them to issue a ticket”.
The reasons for having a tolerance at all are explained in my blog article of September 2007. If the Roads and Traffic Authority staff had read this, they could have saved themselves a lot of embarrassment, and the newspapers a lot of column inches.
One thing though- you can’t change the rolling circumference of a steel-belted radial tyre by varying the tyre pressure (within normal tolerances of course). The steel belts prevent the tyre from expanding. That’s what they are for.