Would you want a spaghetti junction in your neighbourhood?

In a plan that takes the popular level crossing removal program but flips it on its head, the State Coalition have announced they will grade-separate 55 road intersections around Melbourne if elected in 2018. (Reports: ABC / Age / Herald Sun)

Here’s an animation created by the Coalition:

And here’s the list of intersections announced so far:

  • 1 Torquay Road and Settlement Road, Belmont
  • 2 Barwon Heads Road and Settlement Road, Belmont
  • 3 Point Cook Road and Princes Hwy, Point Cook
  • 4 Geelong Road and Somerville Road, West Footscray
  • 5 Ballarat Road and McIntyre Road, Sunshine
  • 6 Ballarat Road and Geelong Road, Footscray
  • 7 Gap Road and Horne Street, Sunbury
  • 8 Mickleham Road and Broadmeadows Road, Gladstone Park
  • 9 Sydney Road and Cooper Street, Somerton
  • 10 Sydney Road and Mahoneys Road, Campbellfield
  • 11 Plenty Road and McDonalds Road, South Morang
  • 12 St Georges Road and Bell Street, Preston
  • 13 Albert Street and Bell St, Preston
  • 14 Banksia Street and Lower Heidelberg Road, Heidelberg
  • 15 Fitzsimons Lane and Main Road, Eltham
  • 16 Fitzsimons Lane and Porter Street, Templestowe
  • 17 Williamsons Road and Foote Street, Templestowe
  • 18 Whitehorse Road and Springvale Road, Nunawading
  • 19 Springvale Road and Burwood Hwy, Vermont South
  • 20 Springvale Road and Ferntree Gully Road, Glen Waverley
  • 21 Princes Hwy, Springvale Road and Police Road, Mulgrave
  • 22 Stud Road and Wellington Road, Rowville
  • 23 Princes Hwy and North Road, Clayton
  • 24 Dandenong Road and Warrigal Road, Oakleigh
  • 25 Nepean Hwy and Glenhuntly Road, Elsternwick
  • 26 Nepean Hwy and North Road, Brighton East
  • 27 Nepean Hwy and South Road, Bentleigh
  • 28 Warrigal Road and South Road, Moorabbin
  • 29 Nepean Hwy, Warrigal Road, Lower Dandenong Road, Mentone
  • 30 Boundary Road and Governor Road, Mordialloc
  • 31 Heatherton Road and Hallam Road, Endeavour Hills
  • 32 Racecourse Road and Bald Hill Road, Pakenham
  • 33 Thompsons Road and Western Port Hwy, Lyndhurst
  • 34 Hall Road and Western Port Hwy, Cranbourne West
  • 35 Moorooduc Hwy and Cranbourne Road, Frankston

My initial thinking: grade separating suburban intersections is a terrible idea.

It has the potential to be extremely hostile to pedestrians and cyclists, as well as businesses and other properties immediately adjacent the roads affected.

Melbourne has rightly moved away from grade-separated intersections, eg King St/Flinders St, where the City of Melbourne noted:

One of the principal benefits of the redevelopment of the former Fishmarket site and removal of the Flinders Overpass is that it reconnects the city to the river. The Flinders Street Overpass has provided a physical and symbolic further barrier ensuring that the city ends at Flinders Street. The provision of a variety of activity on the former Fishmarket Site will activate that corner of the city significantly compared to its current role as a public carpark and impound facility.

King Street overpass (October 2003)

The Coalition’s new proposal goes backwards. And it includes signalised right hand turns, as well as signalised pedestrian movements across the road above, negating much of the traffic moving benefit.

It’s unclear how many of the projects would require land acquisition to provide space for the ramps. That’s the problem with grade-separated road intersections – unlike rail/road grade separations (which benefit everybody, not just motorists), they are very space-inefficient.

And all this to achieve continuously flowing traffic that would ultimately have no long-lasting effects thanks to induced traffic.

There might be a short term benefit to people driving through your neighbourhood. But given there are no proposals to remove all the traffic lights along any one particular road, motorists might miss one set of lights, only to get stuck at the next.

For everybody else — those who walk, cycle, or even drive locally — a spaghetti junction in your suburb would be an overwhelming negative.

If you want a taste of grade-separated intersections, check St Kilda Junction. It’s huge, it’s horrible to ride a bike or walk, traffic movements are restricted/convoluted (eg Queensway southbound onto St Kilda Road), and to achieve it they bulldozed numerous buildings including the Junction Hotel.

Designs may have improved, but they can’t solve the basic problems of geometry. Moving lots of cars requires lots and lots of space.

The State Coalition seems to have transport policies varying from the excellent (trains every ten minutes, every day — a policy that was announced in March but is still worryingly absent from their web site) to the dire (roads, roads and more roads, including building so many motorways at once that even the RACV said it was over-the-top).

It’ll be interesting to see if this particular proposal gains traction.

PS. With thanks to Arfman for the inspiration, though I’m sure someone else can do a better job:

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20 Replies to “Would you want a spaghetti junction in your neighbourhood?”

  1. “There might be a short term benefit to people driving through your neighbourhood.”
    Yes, the Nepean Hwy overpasses could potentially save me time when driving through Moorabbin as I do on most weekends.. But only until the next set of traffic lights a few hundred metres away.

  2. There seems to be much less traffic in the “After” animation. If only. We know that increasing road capacity increases traffic, but the Coalition has tried to show raindbows and unicorns (and less traffic) in the grade separated version.

  3. Excellent points: the outcome for cyclists and pedestrians is quite unclear. But the animation also conveniently ignores that line of traffic waiting to turn right. Where do they go?

  4. For all of the claims for a preference for underpasses (note the slippery language), some of those intersections will be ‘Skyroads’. Using Fitzsimmons Lane as a familiar example, Main Rd / Fitzsimmons Lane will be an overpass due to the hill on Fitzsimmons Lane to the south of the roundabout. The alternative is to lower Main Rd but this will affect Bolton St and likely the shops there, and I can’t see how it can be done within the existing footprint. Porter St is straightforward but Foote St isn’t as the intersection has a hill to both the south the west, and to the east. If I lived around that intersection, I’d be very concerned.

  5. Does this mean no more rail grade separations ? This is going to consume a lot of budget, and it’s unlikely both can be done at the same time.

    Where is the economic analysis ? Why were these road/road grade separations placed above road/rail separations, such as Mt Derrimut Rd near Deer Park Station, which has become virtually unusable since the number trains has increased with the Regional Rail Link. A previous Liberal government removed grade separation here from the scope of RRL, as a cost saving measure, which has made Mt Derrimut Rd virtually useless at peak hour because there are so few breaks between trains.

    The large amount of simultaneous road construction is going to push construction prices up, with the NE Link, E-W link and Western Distributor also competing for similar equipment and a similar skill set.

    Most of these are in outer suburbs where there is already little walking or cycling, but these new intersections aren’t going to encourage it. The continuous flow of traffic through the grade separation is unfriendly to pedestrians because there aren’t breaks in the traffic to cross.

    One that the RACV has been pushing – Hoddle St/ Vic Parade – didn’t make the list. Perhaps the Libs weighed the political cost and thought it was too great.

  6. Most of those junctions have significant turning traffic and large tidal volumes which is not addressed by the pretty images shown, and the posters above have already pointed out the close spacing of signalised intersections which limit the throughput of such flyovers anyway. It makes cohesive designs like the west gate bridge (tunnel) project seem sensible in comparison.

    How about they spend the money on grade separation of pedestrians (and/or cyclists) to increase the throughput and eliminate pedestrian clearance time.

  7. First off, they are doing something similar over in Adelaide, with their South Road. I was over there a few weeks ago, and found out the hard way.

    They missed a few great opportunities. They could have done Springvale road at Nunawadding with both the train line and the highway at the same time by putting Springvale road under both at the same time.

    Having said that, I would prefer it being spent on public transport.

  8. They are going to need to do property acquisitions and utility relocations, they might as well turn to road network pricing and use the money for underground freeway extensions and metro projects, at least with the Citylink and EW Link a large amount of traffic is under the city not through it.

  9. As a ex-Melbournite now living in Harbin, China, these types of intersections are quite familiar to me. There are many of these types of intersections here in the main part of the city (think of a radius from the Melbourne CBD to about Clifton Hill/Northcote).

    I could see some possible advantages for making some roads, like Hoddle/Punt (north of the Yarra), into a semi freeway as long as you’re going straight, but overall I think the main problems remain. You still have traffic lights on the surface level, it’s likely to be expensive, the trench is rather long to accommodate the gradient (particularly for buses, trucks and trams) and induced traffic is likely to swamp the early benefits anyway.

    I would also point out that very few of the grade separated intersections here are like those in the video (i.e. ground level plus a underpass). Many also have at least one overpass, while one major example (on the way to the airport) has an underpass, an overpass and a left turn overpass over the top of it all (people drive on the other side in China). It’d be interesting if the Liberals have anything like that planned after all the fuss they’ve kicked up over “Skyrail”.

  10. Building an underpass at north road/nepean hwy sounds like a great idea! Don’t worry about the fact that it’s a flood zone or has a creek and a significantly large drain running under it! Or that it has two other intersections (Martin st & Bay st) literally only a few hundred metres on either side of it where you’ll have to stop again anyway.

  11. Just in response Tranzit Jim’s comments. The South Road project in Adelaide is a little different I would say as it’s essentially a long term freeway project connecting two existing freeways along the only North-South arterial in the city. Compared to the Melbourne proposal which is random intersection projects all over the city. The Adelaide project also, to varying degrees of success, incorporates cycle connections and level crossing removals.

  12. @Kevin Most level crossings will be contracted for removal by 2018 so the remaining few probably can be cancelled if the LNP were to win power but I do not think they will cancel the last few as it would be impractical.

    @Face Palm, it makes you think why bother with a few intersections spread throughout the metro area, instead implement road network pricing and start building a fully underground freeway that can replace the Nepean Highway as a major thoroughfare for the bay area. Another interesting fact is that many removals run parallel to major freeways such as Springvale and Dandenong roads and the soon to be built North East Link. It may be a lot of this traffic is a result of toll avoidance.

  13. @Llib, I don’t mean the contracts, I mean the actual physical level crossings that have not even been listed in the 50. Level crossings that are near major road intersections might still get grade separated with this policy, but how many is that and how many others remain? Egs Gaffney St and Devon Rd crossings on the Craigieburn line?

  14. I can’t see how removing some and not others close by will help with congestion.

    Ballarat Rd/Geelong Rd is a T-intersection – not sure how that would go, since all traffic from Geelong Rd goes onto Ballarat Rd. Geelong Rd/Somerville Rd – this is a six-direction intersection because Roberts St runs north-south through it – presumably Geelong Rd goes under, and you still have an intersection of Roberts St and Somerville Rd? Ballarat Rd/McIntyre Rd – there is already an overpass of Ballarat Rd over St Albans Rd and the railway line at Albion very close by.

    Surely none of these can be done without significant property acquisition or reduced capacity.

  15. @Steve: not only does the six-way nature of Geelong Rd / Somerville Rd / Roberts St provide challenges, it all sits atop Stony Creek, which runs NW-SE under the existing junction. Have fun putting an underpass through the creek!

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