Ask Phoebe: Stick with speedo to keep on right side of police

Q. With the police crackdown on traffic speed, which is likely to be closer to the real speed - the car speedometer or the GPS? I believe most speedometers are traditionally a bit optimistic. Mine consistently shows about 10 per cent higher than the GPS at speeds greater than 50-60km/h. If the police are going to reduce the margin of error, it would be nice to know which device to take the most notice of, without slavishly watching both and not the road. Gary Arnold, Auckland.

A. Jack Biddle, technical advice manager at the Automobile Association, said that in recent speedometer tests, the AA found the difference in indicated speed vs the actual speed was within 6 to 8 per cent. All the vehicles tested displayed a speed faster than the actual road speed.

International standards require car manufacturers to overestimate actual speed, but discrepancies creep in depending on tyre pressure and wear.

Your GPS should be used to confirm the difference in actual vs indicated speed only. If you go by your indicated speed, this should reduce the risk of being caught travelling at over the legal limit.

For example, where a traffic officer clocks a motorist at, say, 105km/h, the motorist's indicated speed would have been greater than this.

In most cases, a vehicle's speedometer is positioned where it is most appropriate for the driver and which allows the driver to concentrate on the road ahead, the surroundings and the indicated speed.

It would take only a wee lapse in concentration, said Mr Biddle, for a car to go over the legal limit when the GPS was being consulted.

Q. There is a proposal to erect a life-sized bronze statue to the only New Zealand-born world boxing champion, "Torpedo" Billy Murphy, in Ponsonby. According to the Dictionary of New Zealand Biography, Thomas William Murphy was born in 1862 in James St, Arch Hill. In my Auckland street directory, there is no James St in Ponsonby. Where has it gone? Nobby Clark, Grey Lynn.

A. The Auckland City Libraries website, in the section on Auckland street names, advises that James St in Arch Hill had this name until about 1935, when it was changed to Putiki St. It runs southeast of and parallel to Great North Rd, between Kirk and Burns Sts.

Q. My son recently failed his restricted motorcycle licence test. The memo from the testing officer reads, "Failed to give way turning right out of St George's Bay Rd into The Strand. Cars waiting to turn right from The Strand into St George's Bay Rd". My understanding is that, when turning right, you don't have to give way to traffic on your left waiting to turn right as long as the road you are entering is clear from both sides. In this case the vehicles turning right into St George's Bay Rd were waiting on a give way sign and there was no traffic on either side of The Strand. Can you shed some light on this issue? Sandeep Paul, Auckland.

I certainly can. I went out for a look, and I'm sorry, Mr Paul, but your recollection of this intersection is faulty. The give way signs are on St George's Bay Rd, not The Strand, so that any turning traffic leaving St George's Bay Rd must give way, or at least be prepared to do so, to traffic on The Strand.

But you are correct in your understanding of the give way rule.