When you drive the Southern Motorway between Rolleston and Christchurch, how fast do you go? 

According to the mayor of Selwyn, Sam Broughton, chances are you go faster than 100 kph. Which is why he thinks the speed limit on that piece of road should be lifted to 120 kph. 

An idea which I think is ridiculous.  

I’m thinking it probably has something to do with the come-to-Jesus moment I had about speed limits when I was travelling around the South Island last summer. When I realised that doing 80 kph on a 100 kph is, actually, quite enjoyable. And safer. 

I used to be all-for getting back to the old 50 kph and 100 kph. Not so much now. 

Where this idea of the Selwyn mayor's has come from, is the work the Government’s doing at the  moment reviewing speed limits around the country. 

Quite rightly, it’s got its sights set on some of the non-sensical speed limit changes that have popped-up around the place recently.  

And some of the speed limits you see are nuts. Case in point: Colombo Street, in Christchurch, heading towards the Cashmere Hills. It reduces for a very short stretch because of a nearby school - which isn’t even on Colombo Street. 

Then you go a bit further up the road to where there is a school on Colombo Street, but there’s no speed reduction! 

So Transport Minister Simeon Brown has sent around a document to local councils asking for their feedback. 

And what the councils are being asked to do is give advice on highways they think should have a speed limit of 120 kph instead of 100. 

And Selwyn’s Sam Broughton has told the Government that that beautiful stretch of motorway from Rolleston to Brougham Street should have a speed limit of 120, because a lot of drivers are travelling faster than 100, anyway. 

Which is an interesting way of justifying it. ‘Oh look, they're breaking the rule so let’s change it.’ 

He says in his letter to the Transport Minister: “Whether it is for general traffic, direct public transport services, or moving freight, council considers increasing the speed limit of the motorway between Rolleston and Brougham St will assist in improving efficiency and connectivity while still being safe.” 

And he goes on to say: “This is reflected in generally higher average speeds above 100 kms per hour we already observe along the motorway.” 

So that’s the bit where he’s saying people break the rules anyway, so let’s change them. 

Since the Southern Motorway opened in 2020, five people have been seriously injured in crashes. There have been no fatal accidents. 

And the number of vehicles using the motorway is just going to increase. In 2021, there were 21,000 vehicles on the motorway daily. This is expected to jump to 33,000 by 2040. 

I’m not the only one who thinks it's a stupid idea to increase the speed limit. Transport expert Professor Simon Kingham —from the University of Canterbury— feels the same. Which, you might say, he would anyway, because Simon’s not big on speed. 

He’s probably not that big on vehicles, full stop, to be fair. But I agree with him on this one. 

Because he and I only see one outcome from increasing the speed limit to 120 kph on the Southern Motorway. More crashes and more severe crashes. 

Because if it’s 100 now and the Selwyn council is noticing that a lot of people are going faster than that, what do you think they’ll do if it’s 120? They’ll go even faster, won’t they? 

I remember a few weeks back, we were talking about restricting the engine size for young or new drivers, and there was no shortage of people saying you can drive a Demio or any one of those shopping basket cars upwards of 150 kph. 

So if you increase the speed limit on the Southern Motorway, as the mayor of Selwyn thinks we should, then I think we can pretty safely assume that there’ll be a lot of drivers quite happy to nudge it up to 130 kph. And that could be disastrous. 

Which is why it’s a “no” from me.