There's a section of the highway that reminds me of that old Irish blessing: "May the road rise up to meet you . . ."
It's just across the Hurunui River, at the south end of the Balmoral forest a few kilometres on the tamer side of Culverden.
It used to happen in about three or four different places but the engineers, too removed from their childhoods to know any better, have levelled it out in all but a single instance, so you get the butterflies only once.
They come in a rush as the car dips at speed on the straight, rises sharply, then dips again - and for a few micro-seconds the whole of you remains suspended, light, almost breathless, a load lifted from the deep innerness, from the sameness and the feet-on-the-ground stolidness that anchors you and miraculously, for an instant, you are weightless as if such mundanities no longer existed, only a vacuum-filled cavity of possibilities - and brightly coloured Lepidoptera.
What would it be like to exist permanently in such a state, you might wonder, but the road dips and your innards settle.
I have never really turned my mind to the science of it, but I imagine roller coasters work on the same principle.
I've never been much of a fan of fairground rides.
Why would you be when you can get the same precious effect on State Highway 7 every year or so - one small delight to be anticipated and savoured, rather than engorged and (likely as not) disgorged amid the stomach-turning shrieks of fairground fellow-travellers.
This is the first highway I recall with any great clarity.
It cradles the first journeys of my childhood, the great treks from the West Coast to Christchurch and to the solitary white house in Cunliffe Rd on the outskirts at Styx marking journey's end.
My grandfather was a railway man, who followed the tracks from Greymouth to Bluff, from Ashburton to Balclutha - and after a sojourn at Macandrew Bay, where ill health and an early retirement took him - to the northern reaches of Christchurch.
He was station manager by the time he gave it away, which in the days when rail was king, was not to be sniffed at.
Perhaps that's why they named the road after him; or perhaps it was simply because he and his family were the sole residents and imagination in those early post-war days was at a premium.
I digress. The road.
In my memory the direction of travel is almost invariably east and south, landmarks burnt into the memory from the very outset: the steep hill just over the Buller River where we used to run the soapbox derby; the bluff at Hawkes Crag, blasted and chiselled out of solid rock to form a narrow passage - there was an early photograph at Craddock's garage showing a bus which had to have its tyres deflated to pass beneath.
And there were almost always roadworks.
Not the slow-down, mind-your-speed, and thanks-for-your-consideration sort of roadworks, but real stop-you-in-your-tracks kind of roadworks, where entire hillsides had slipped on to the road, or bridges had been washed away - and had been replaced by bailey (clickety-clack) bridges, and where you might have to pull over and all four of you in the back seat curl up for the night while Mum paced about outside smoking a menthol and Dad shared a billy and chewed the fat with the men from the public works department, attempting to discern the chances of onward passage through a fog of roll-your-owns and laconic discontent.
Occasionally, there would be snow amid tussock on the Lewis Pass.
We'd stop to play in it and enjoy a sandwich or a mug of thermos tea.
Then onward and over we'd go, past the deer stalkers' hut, winding and wending, wending and winding, the humdrum downhill rattle and hum of rubber on road interrupted by the coughing and spluttering of uphill climbs, the yin and yang of motoring in those bygone years.
From the Hanmer Springs turn-off it was plain sailing.
Fair-weather motoring, downhill towards Culverden, then a veritable coast the remaining 60-odd miles, the breeze at our backs.
Travel is too easy today; too removed, too encased and isolated and self-absorbed.
No occasion or reason to wonder who built these roads and why; no opportunity - just the momentum of 21st-century life hurrying us from A to B without a second thought - to let history in.
We drove back up Highway 7 a couple of days ago, chewing up the dispensable, disposable miles, victims ourselves of modernity and haste.
But still I looked forward to the section of highway just over the Hurunui River.
Sure enough the road rose up to meet us.
Momentarily, I felt quite giddy.
Simon Cunliffe is assistant editor at the Otago Daily Times.
