Ask Phoebe: Onehunga rail station work should be finished within three months

Any idea when the Onehunga line will be opening for passenger service? Originally it was supposed to be last December but despite all the tracks being relaid last year, there is still no station at Onehunga. Kathryn Arnold, Onehunga.

How very timely, says KiwiRail. Building of the new station begins this month and should take only two or three months to complete. It is on the corner of Princes St and Onehunga Mall, where the spur line is now.

Traffic on the Southern Motorway heading south travels pretty well until the overbridge at the Mt Wellington Highway, which can be a real bottleneck, as the three-lane motorway reduces to two lanes. Is there a plan to replace the old two-lane bridge with a wider structure? John Bockett, Hillsborough.

Not to my knowledge. I believe the narrowing is a deliberate measure to slow traffic and allow the vehicles from the Southeastern Motorway to get on to the Southern Motorway and head towards the city, and also allow traffic from the Mt Wellington Highway to access the motorway southbound.

Why are petrol prices at the pump given to one or two decimal places per litre, when the smallest coin is 10 cents? Ron Evans, Auckland.

The price of fuel in New Zealand is dependent on the international price of crude oil, the currency exchange rate, and taxes levied on fuel. The decimal points allow the fuel companies to reflect these variables more accurately that rounding the price up or down to the nearest 10c might allow.

Because fuel is a volume purchase - how often would you buy one litre? - the decimal points become absorbed, and can in fact save you money.

For instance, if 91 octane was priced as $1.78c a litre at the pump, 50 litres would cost you $89. If the price per litre was rounded up to $1.80, as the nearest 10c mark, 50 litres would cost you $90.

Of course, the reverse also applies.

I often drive down Shelly Beach Rd from Jervois Rd and turn left into Sarsfield St. Does traffic heading up Shelly Beach Rd from the Harbour Bridge offramp have to give way to me turning left or not? I have always assumed that as I was turning left I gave way to everyone, in the absence of give way signs, but the other day a police car turning across me waited for me to turn first. Jeremy Ashcroft, Auckland.

I assume you refer to traffic coming up Shelly Beach Rd from the offramp and wanting to turn right into Sarsfield. In the absence of any stop or give way signs, left-turning traffic must give way to oncoming vehicles turning right.

Your police driver was very courteous, or perhaps one practising for the mooted change to the right-turn rule.