Much simpler road plan

MICHAEL WILLICOMBE is a Freo resident and former Fremantle council planner with a bit of experience in roads—he designed the port truck link-up by the old Europcar site. He reckons Main Roads’ plans for a roundabout at the corner of High Street and Stirling Highway is a bad idea.

THE High Street junction upgrade is going around in circles…

I must start by saying that I will be one of those to benefit from the upgrade, as I live on Chudleigh Street, which will be cut off from the rat runs to/from Marmion Street.

So I have no hidden agenda when I say how disappointed I am, that after 20-plus years, the draft plan “upgrade” remains so inept from a traffic flow/safety viewpoint.

Not to mention the decimation of existing townscape that would result with the loss of more than half of a whole street block.

From a traffic point of view it’s inept because large roundabouts on major arterial roads become redundant as traffic volumes increase past a certain point.

The UK is littered with hundreds of roundabouts on similar major roads that are now covered in traffic lights—in a circle.

With the added lights the circle becomes redundant: it adds lag inefficiencies to the sequencing of the lights (think roadworks), and it remains a huge waste of space, not to mention a permanent eyesore.

• Michael Willicombe’s alternative plan to improve safety at the High Street/Stirling Highway intersection.

Can you think of a busy highway with heavy trucks in Perth that has a roundabout plonked in the middle of it?

Heavy trucks entering and leaving roundabouts at varying speeds. Yikes.

It would quite quickly become unworkable and unsafe, requiring traffic lights to be retrofitted around it.

Now Main Roads know a roundabout is nonsense: they even say on the phone, “well people want roundabouts…”

Many people still think, misguidedly, that roundabouts are a solution on major arterial roads and the High St/Stirling Highway intersection, unlike any other in history, has succumbed to the horse designed by committee joke—it looks like a camel.

The dedicated lane heading east from Stirling Highway—outside and separate from the roundabout—is designed at such a huge radius that trucks won’t have to slow down at all, until well after Marmion St.

This is too high a design standard considering it would result in the decimation of a whole street block.

The critical design criteria should be that trucks and other vehicles can maintain a “reasonable” speed during the turn and not have to stop and start.

A modest radius with a generous positive camber would be perfectly adequate to keep any truckie happy.

You’ll notice the dedicated lane currently proposed is at such a large radius partly because it has to avoid that large roundabout.

You may see a pattern developing here.

For trucks heading to the port, one less set of traffic lights makes what difference?

Very little it seems to me. Would shuffling on and off a busy roundabout be noticeably quicker for truck drivers? Even before lights are retrofitted? I have serious doubts.

You could simply reconstruct this direction of the intersection with improved radiuses and positive road cambers and two lanes turning into Stirling Hwy.

The existing cambers are “negative”, hence trucks occasionally tip over when going too fast around the corner.

Notwithstanding my suggested design amendments, if we genuinely want to solve the traffic problems properly, both directions should have a dedicated non-stop lane.

This can be done by creating a cut/lowered road intersection with an overpass bridge heading to the harbour.

This sounds complicated, but it isn’t. There is already a natural depression and it’s simply a case of lowering the road junction and a modestly raised single-lane bridge; certainly not twin tunnels by comparison.

There is also less compulsory purchase of land required.

This design is much less invasive on the townscape, allowing far more houses and street blocks to be retained.

Pedestrians and cyclists also have a simple short underpass.

One response to “Much simpler road plan

  1. That does indeed sound a lot nicer. The last sentence is probably key in the current design: where are people walking and riding a bicycle to go? MR please design something that takes everyone into account, thank you!

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