There was a letter to the editor over the weekend about the Auckland Harbour Bridge which made a very good point.

The writer remarked that the Harbour Bridge is the coat hanger shape it is because it needed to let freighters in to get to the Chelsea sugar works.

The works are under Birkenhead, and they’ve been there long enough that they’ve become historically significant.

But that is the only reason the bridge goes up so much and down so much.

What a pity we didn’t move the industry in the 50s when we built the bridge.  

What a pity we compromised the bridge for just one industry. We’re going to pay for that dearly.

It’s one of those things we all forget about when talking about a second Harbour crossing.

At the moment you’ll see barges doing Geotech in the middle of the Harbour. It's for two new, three-lane road tunnels. A single light rail tunnel is also part of the plan. 

Meanwhile the existing bridge gets lanes for buses and cycling.

What we get wrong is that we should really be talking about replacing the first crossing because it’s at the end of its life. 

Move the sugar works and we could replace the bridge with a flatter wider version that will be wider and stronger than what we’ve got, giving it a longer life.

I keep reminding people that the real problem with the Auckland motorway system is the limits on spaghetti junction and the pinch points at Northcote and Greenlane Penrose. 

Not the bridge. Which still has more capacity. But no structural strength.

And for all of you not in Auckland wondering why I’m talking about this, it’s simple.

This will be the biggest and most complex and most disruptive infrastructure project this country will see and we’re all going to have to pay for it no matter which city we live in.