The World's Longest One Way Freeway - Rise and Fall of the Southern Expressway
The World's Longest One Way Freeway - Rise and Fall of the Southern Expressway

The World's Longest One Way Freeway - Rise and Fall of the Southern Expressway

The Southern Expressway in Adelaide, South Australia took the title for the world’s longest one way road. Why was it built? And why did it its reign end?


I'm currently driving on the Southern expressway in South Australia. And when this road opened in 2001, it took the title for the world's longest one-way road. That is a reversible freeway, which only goes in a single direction at a time. And this is a 20-kilometer road that connects Adelaide with the growing beach side area of Noarlunga.

And here's how it worked. From 2:00 a.m. to 12:30 p.m., the road would be available North. So commuters could head into the city. Then at 2:00 p.m., the directions would switch for the next 10 hours. And in the time in between, contractors would drive the length of the freeway to make sure there are no breakdowns. Boom gates would go up and down and signs would change. Now that was the timing on weekdays, and on weekends, it would be switched. They wouldn't need to be a change over on Friday night or Sunday night. Now that sounds a bit confusing. Well, it kind of is. That's a downside of a one-way road.

So you might ask the question, "well, why do it?" Well, it all came down to money. In 1991, the State Bank of South Australia collapsed. And it was a government-owned bank, and they were responsible for underwriting all of the deposits. So that had huge economic impacts for the government. And it influenced things for a long time after, including making the choice to make a one-way road. And in doing so, they saved around half the cost, or $68 million. And the road worked. It cut down on commute times, it makes for an easy drive, but there is one downside to it. It's embarrassing.

And this road became a joke, both inside the state and outside. And one journalist wrote, that the "One way highway that became shorthand for all that was wrong with the state. It was a symbol of a state that lacked vision, ambition, and went around things in a half-assed manner at best."

So after a decade of these jokes and laughter, it was a decision made that things had to change. The federal government, the state government, and the state opposition leader, all put forward policies to make it a dual direction road.

And the decision was eventually made. In 2011, construction started. And in 2014, the road opened both ways. And it had to hang up its title of King of the one-way roads. And when it opened, the transport minister said this; "For many years, the one-way road was an embarrassment and a source of frustration for the motorists."

And it's kind of worth noting that embarrassment came first and motorists came second. And that upgrade and the $68 million they saved, well, just 10 years later when they did the redevelopment, the total cost was $407 million.

It is a nice road though.

Thanks for watching, I'm Julian O'Shea. If you enjoyed this, please do subscribe and share it with anyone else that might like it. That's it from me.