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All
There has been a flood of email about this topic. I have decided to reduce the traffic by compiling today’s messages into one email. Please see below.
Another digest tomorrow…
David
Guys this may be of some use from NZ……..
23 Mtr B/Trains – 20 Mtr first to last axle – go anywhere @ 50tonne Gross, permitted for select routes from 50tonne > 65tonne
Quad units go anywhere @ 44tonne, permitted select routes from 44tonne > 48Tonne
Tractor & Trailers have full safety features as per attached, now including Lane Departure & Blind Spot Proximity.
Regards,
Greg Pert
Managing Director |Owner
Cell: +64 21 930078
The Liquid Logistics Experts
Right product, right quantity, right tank - ON TIME - GUARANTEED!
Hi everyone Turns out the pioneer Australian state for B-doubles was probably Western Australia. The attached Parliamentary report from New South Wales published in 1990, states that WA allowed B-doubles as soon as 1983. Hope this helps. Some of the safety observations from this 1990 report are still relevant. Have a great day all. Matthew Bereni
Hi Chet and Johan and Ale,
I want to add a little bit here from my exposure mostly to the Australia context and my background in vehicle dynamics, as well as some context behind the statistics that Kim will have presented at the last HVTT.
We do get icy roads in Australia, just this week much of the southern regions of Australia including highly populated areas have been below 0 Celsius.
Chet,
This is certainly correct that tyre pressures play a big part in maintaining longitudinal and lateral stability of a tyre, regardless of friction surface, as well as many other benefits.
Johan,
You have mentioned correctly that the jack-knife risk increases with speed, in Australia it is very rare to see any medium to long haul unit other than a semi or b-double. Nearly all rigid combinations operate short to medium haul. This means that the b-double and semis are doing far more km and at higher speeds, so you would expect to see these combinations more highly represented in jack-knife incidents in Australia.
Furthermore, it is only until very recently that ABS has been mandated in Australia on vehicles other than a prime mover for B-Double use. We are many years behind Europe and America on this.
Conversely, there are also numerous things that reduce our jack-knife risks compared to that in Europe. It is very rare to see single axle drives axle groups in Australia, most are 6x4 tractors/prime movers or trucks, but there are some 6x2 and 4x2, but these will mostly be doing short haul work around metro regions and more doing the km or as many high-speed km as our long-haul fleet. The added drive axle adds weight, length and tyre foot print which all adds to additional lateral stability for the tractor unit which minimises the jack-knife risk.
Ale,
I think it is important for you to consider that whilst in Australia the B-Double began trials in the mid 80s, it was not until 1992 that they were no longer “on-trial” but accepted.
Even today B-Doubles for not have access on any road network, they still operate under what is called a Class 2 notice (for more information see here https://www.nhvr.gov.au/road-access/mass-dimension-and-loading/classes-of-heavy-vehicles/class-2-heavy-vehicles)
From a policy perspective, you should consider establishing a trial period, this will alleviate some of the concern for people, select specific routes for these trials to be run on, and gradually expand the routes as you become confident of which routes are suitable and which routes are not. You can then use these routes to run vehicle demonstrations as well.
You could perhaps talk to Bob Pearson about how the initial trials were set up for B-Doubles in Australia and how you could implement similar trials to manage people’s concerns.
Kind Regards
Robert JG Smedley | 0422 920 980 | [log in to unmask] | www.smedleys.co
Alfons,
This is a good point that I should have mentioned.
In Australia, there are many different types of B-Doubles, but three main ones, the 20m, 25-26m and 30m. Each of these have very different access levels depending on the suitable of the routes they intend to run on (bridges, turning bays, lane width, etc.)
You could require some or all the steps Alfons mentions below to grant access to your trial/network. You could also run some PBS analysis to benchmark your existing vehicle fleet, and develop a concept B-Double that performs within a very similar performance envelop.
This would greatly help you in alleviating the concerns in your communities.
Robert JG Smedley | 0422 920 980 | [log in to unmask] | www.smedleys.co
Dear all
The stability of any combination in respect of rollover is very dependent on suspensions fitted to the axles. Too soft and excessive lean leads to instability; to stiff and the unevenness of road surfaces leads to significant wandering and hence instability.
The braking performance is also very dependent on suspensions fitted to the axles though researchers and others usually ignore this influence. Very rollover stiff air suspensions – those with fabricated steel trailing arms welded to the axles - combined with small air tube connections front to back are the worst simply because there are huge variations in the loads supported by each dual tyre group – and those variations significantly degrade the breaking of each axle group.
As for jackknifing and traction ability, the key factors are the actual group combinations used, and in particular the drive axle group and the proportion of the overall weight supported on the drive axle group. In Australia our most common B-double combination has a single steer axle and six tons, a Tandem drive axle group is 17 tons; and tri-axle groups at 22 1/2 tons, with a maximum gross of 68 tons. So 25% of the mass is supported on a tandem axle drive group which is much more resistant to jackknifing than any single axle drive group. And of course the drive axle group suspension is another critical factor.
In respect of suspensions, the best suspension available worldwide is the Hairebag suspension - www.thehairetruckandbusrepairs.com.au - which comprises air suspensions with mechanical spring trailing arms plus patented large diameter air connections between the axles from front to back. The next best suspensions are the air suspensions with mechanical spring trailing arms. B-double is fitted with these suspensions will perform much better than other B-doubles, especially those fitted with fabricated trailing arm air suspensions.
And arguably the B-double configuration in Australia is the most stable in respect of jackknifing, and with the right drive axle suspension has traction at least as good as other tandem axle rigid truck combinations.
So in summary I think there is a need to specify the all up specifications of a B-double before making comparisons across jurisdictions.
Regards from
John Lambert
MIEAust, CPEng 180785, Member ASME, ACRS, SAE
Bachelor of Engineering (University of Melbourne, ARMIT (Mechanical)
Director and Company Secretary, John Lambert & Associates Pty Ltd, ACN 090 833 873 ABN 59 090 833 873
235 Wandana drive, Wandana Heights, Victoria Australia 3216
Phone: Intl +61 3 52491228 Local 03 52491228
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Email: [log in to unmask] Website: www.johnlambert.com.au
Hi all,
In Denmark the B-double is by far the most popular combination – and running since 2008 with no problems at all.
There is an older evaluation from 2011 here: http://www.vejdirektoratet.dk/DA/trafik/erhverv/modulvogntog/Sider/Evaluation%20(English).aspx
If this can be of any use ;-)
Kind regards
Jørn-Henrik Carstens
Senior advisor, politics and tecnical affairs
T: +45 7367 4547 | +45 4124 3225 | [log in to unmask]
ITD | Association for the Danish road transport of goods
Lyren 1 | DK6330 Padborg | Denmark
T: +45 7467 1233 | F: +45 7467 4317
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EU Transparency Reg.: 404900912463-75
Again, B doubles on Australian roads are our norm. If there was any hint of a problem, our do good, bleeding heart media and greens would be all over it. We have no problems with safety concerns on B doubles.
Chet
Ale
I think the library is a good idea. The IFRTT web site already seems to have the foundation to accommodate such an idea. On the bottom right of their home page they seem to have a list of links.
Perhaps all that ought to be moved to a separate IFRTT "useful links" web page(s). That next web page would show regions and then you'd click through to the region of interest, than a page full of links and so on.
I can easily imagine an Oceania links page having over 20 links to information (or organisations) of interest just in Australia and New Zealand alone.
Regards
Paul Caus