Ask Phoebe: Sign makers all on the same track

Who makes the big motorway signs? Is it one company or a number of them? There does not seem to be much variation between regions - are there some specifications that the manufacturers have to stick to? Kevin Jones, Pukekohe.

There are several sign manufacturers around the country. The main one in Auckland is RTL in Mt Wellington. All the sign makers adhere to the standards and specifications outlined in the Transport Agency's traffic signs and markings manual. If you'd like to know more about the legislation, visit www.landtransport.govt.nz/rules and go to traffic control devices.

And, in similar vein,

I was travelling south on the new Puhoi-bypass toll road and noticed the signs near the toll-point changing colour. From a distance, the signwriting was pink, but as we got closer, the lettering and borders on the same signs was yellow. Was I seeing things? Or is this some new sign-writing technology? And, if the latter, what is its purpose? Tessa Farnsworth, Mt Roskill.

Optical illusion, I feel, is the reason. The signs on the Northern Gateway Toll Road, to give it its full title, have a blue background with yellow writing and trim, so they are clearly visible. The yellow writing may have looked pink from a distance because of reflection from the sun as you approached the sign. There is no clever new technology - the effect you saw was merely the result of natural light.

I was reading about the new sewer tunnel under Hobson Bay and how the old surface pipe will be demolished. Does the council have any plans to retain some of the old structure to provide access for a cycleway/walkway across Hobson Bay? Doug McGibbon, Epsom.

No. All of the old pipeline structure will be removed. Even though the reasons for the sewer pipe replacement are economic and environmental, there are recreational benefits to be had from not having a pipeline blocking access to the major part of Hobson Bay. Groups such as the Auckland Rowing Club see opportunities for rowing, kayaking, dragon boating, waka, small yachts, outriggers, Sea Scouts and swimming.

In the old days, distances between towns were measured from post office to post office. With a number of these now closed, from what points are these measurements now taken? Robyn Smith, Auckland.

Distances are now measured between the "recognised centre" of each town. In days gone by, this was traditionally the post office, as you note, but the closure of many of these in the 1980s, under the Lange Government, created a difficulty, so now the centre of town is the start and finish point. In Auckland, distances on the motorway are measured between offramps.