KEY POINTS:
I am a daily early-morning walker on Tamaki Drive, and wonder how the port authorities manage to get all the lights on the marker buoys to flash simultaneously? They cover a large area but all flash in unison. And they look great. Spencer Maxwell, Orakei.
Technology is wonderful, isn't it? The shipping channel markers, all 20 of them, have global positioning system (GPS) units synchronised by satellite clocks, so that they all work together, as you have observed. The buoys are also fitted with AIS (automated identification system) transponders, so each is clearly visible on screen both on the vessel in transit and in the harbour control centre. Clever stuff indeed.
The system was installed in the middle of last year, at a cost of $27,000 to $28,000 per buoy, to keep Ports of Auckland in line with international best practice.
The co-ordinated lights, red on the port (left) side coming into port and green on the starboard side, flash one second on, one second off to give a runway effect similar to that at an airport.
The red buoys have even numbers and the green buoys are odd-numbered. The entrance to the commercial shipping channel is marked by "A" buoy, which is red.
Auckland harbourmaster John Lee-Richards says only four or five shipping ports around the world have such a system in place.
The red/port and green/starboard convention is reversed in ports in the Americas, Japan, South Korea and the Philippines.
I am wondering what contingency plans Transit and North Shore City have in place that would allow cars to use the new busway during times when stopwork meetings and strikes force commuters back into their cars. Or are they assuming this situation will never arise? Dave Sidders, Devonport.
Both Transit and North Shore City considered this and similar situations during the design of the busway.
The busway is separated from the motorway by more than 5km of concrete safety barrier and it would be an expensive exercise to reconfigure it for such a rare event.
As well, the busway is specifically designed for bus use only, and it would not be practical, safe or effective to have large numbers of cars on it. The busway's two lanes are not separated by barriers, and the stations and interchanges are not designed for large numbers of private vehicles.
So, no cars on the busway, not now, not ever.
I am wondering if you could settle a minor dispute between friends. When were the vehicle weight restrictions lifted from the Newmarket motorway overbridge? My memory tells me that vehicles were limited to a maximum tare of two tons, but this was some time ago. Brian Griffiths, Auckland.
I fear your memory is playing tricks, sir. Transit staff, both ancient and modern, have no record of any weight restrictions on the Newmarket Viaduct in the past 10 to 15 years, and it is thought to have been most unlikely before then. Any weight restriction on such a busy and essential part of the motorway would seriously compromise its effectiveness.
