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VIC The science behind 50kph limits

Discussion in 'Politics, Laws, Government & Insurance' started by trd2000, Jul 19, 2016.

  1. reading through research papers as usual to refresh my memory, came across this little nugget..... holy shit, victoria really just made up figures for the results of their change from 60kph to 50kph urban limits? there's nothing quite like science to get results, and this is nothing, at all, like science....

    "Victoria The likely benefits which were considered in the Regulatory Impact Statement (RIS) (4) for the introduction of a 50 km/h default urban speed limit in Victoria were reductions in crashes and reductions in fuel consumption (which consequently reduces vehicle operating costs and greenhouse gas emissions).

    Based on the NSW results, the RIS chose a 7% reduction in casualty crashes and a 16% reduction in propertydamage only (PDO) crashes as the lower limits of the possible crash reductions. Based on Kloeden et al.’s (5) work and assumptions of less than complete compliance, a figure of 15% was chosen as the likely upper limit of the possible reduction in casualty crashes. The upper limit for PDO crashes remained at 16%, given no other data."


    now, when the 50 limits came in the road safety nut jobs were predicting a 25% reduction, cause that's what zurich got, or 45% cause thats what norway got........ turns out that all the other states, who were more dependent on science than victoria, measured less than 10% improvement. Victoria just upped the TAC advertising budget to cover the lack of evidence.

    What's more, I doubt the figures from the other states, and i very much doubt the integrity of the figures from scandinavia that were used to justify the change, even though i'm not completely adverse to the change itself, just the enforcement regime.
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  2. so it's all about the costs of crashes then
  3. One aspect that is not apparent in the RIS is that the policy platform was developed by the then Labor government as an budget measure, with a guaranteed compliance fail rate built in to ensure that the stream would continue unabated. Whether or not it would (or does) stand up, the science was always led by the finances.

    The RIS provides upper and lower estimates for reductions in fuel consumption and greenhouse gas savings resulting from the 50 km/h initiative. The upper bound estimates are based on figures in Austroads (6) and Roper and Thoresen (1996, cited in 4). This assumes that a reduction of 1 km/h in average speed will reduce fuel consumption by 0.3 per cent, translating into an annual fuel saving of 1.8 million litres.

    That always struck me as somewhat counterintuitive, but I never did find the paper. Plausible for a majority, or not?
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  4. i always have my suspicions about such things, but hadn't looked into it for victoria..... it's certainly true with NSW. the fines were put up to help acieve a surplus, and the whole safe speeds program pivoted on the increased non-compliance rate achieved by sub 85th percentile speeds, and subsequent targeting of safe areas, where <85% of drivers believed the speed limit to be appropriate, with mobile speed cameras. In Tasmania, the labor govt attempted the same reducing open road speeds from 100 to 90, but made the mistake of assuming a trial would support their case and when it increased deaths they had to backflip..... and of course the NT labor govt who brought in speed limits and highway patrol with absolutely no evidence, but reaped the financial rewards.
  5. It's always to do with $$$$. I've got a senate document here that I've scanned over, so I can't recall the exact numbers.
    A 30-50 year old male represents a community worth of a few million dollars, it's got nothing to do with the sadness of death.
  6. seems they underestimated the belligerence of Victorian motorists :p

    the problem with statistics (for example).. is that if the people who do drive 50 didn't have accidents before.. and the people that drove at 70 before and crashed, still drive at 70 and still crash...
    the stats will show there was little reduction due to change in speed limit.

    the change will only come with change in driver behaviour... but we all know better than some arbitrary rule (until we don't)

    dumb people being dumb cause the big stick to be waved.. but many are too dumb to realise why the stick was waved, and continue to do dumb things :)
  7. TAC making up statistics or facts to support government policy? Never.......

    But Dw, they have a crash lab at Monash Uni and 'experts' who will say anything you want them to in the name of safety.
    -70 and 90 zones are to confusing for motorists, better to just cut them back to 60/80
    -Wire barriers are perfectly safe for motorcyclists, we've never tested a bike against one but their safe
    -Low level speeding is dangerous, reinforced with the controversial motorcycle crash video where the car pulls out infront of a bike doing 68km/h in a 60 zone which obviously (dahh) resulted in the car not seeing him.
    -Speed cameras save lives, even more so when the tolerance is turned down to almost 0%
    -Reduce the CBD to 40km/h to lower injury to pedestrians
    -Fluro jackets save lives
    -Filtering is dangerous
  8. Fixed it for ya. ;)
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  9. So "every "K" over is a KILLER", will become "every Decimal over is DEADLY" as treasury recommend lowering speed limit tolerance to the absolute minimum in order to keep the inflows up. The relevant government departments will be charged with driving the message home, charging motorists and keeping the revenue stream healthy. Those that disagree with the big brother message will be ridiculed and viewed as having no regard for safety.
    Heck, they will probably shoot adds with kids walking out in to the road and the motorist doing 50.5Kph, yes .5K over is enough to end their life and leave a family in grief and the motorist charged with murder, and having to live the rest of his life knowing that, yes, EVERY DECIMAL IS DEADLY!
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  10. I agree with you on this.... but I also kind of agree with the lower limits. I've had a fair amount of time getting ready for court to contemplate this, and bearing in mind i was caught in a 50 zone, thinking it was a 100 zone, I'm reasonably happy with the different approaches. That said, I think the 40 zone should be restricted to areas where there is extremely heavy foot traffic..... superficially 40 is optimistic in the CBD anyway... so it wouldn't make a lot of difference. but putting that aside, here's my reasoning:

    There are two methods/philosophies behind reducing the road toll, firstly reduce the number of accidents, secondly reduce the impact of those accidents. Both work. We have recently been focusing on a "safer speeds" approach where accident energy is limited. Where vulnerable road users are concerned it's pretty much essential to get speeds below 38kph (25mph) (human running speed and one of the test speeds for the original circa 1970 survival data). as a hypothetical, look at these situations-
    1. you're driving along a suburban street, you see someone walking along the footpath, you begin to MONITOR them before you pass them, they step toward the road and you are able to apply your brakes before you hit them..... you've scrubbed off enough speed to hit them below 40kph and they're bruised, but they live.
    2. you're driving through the CBD, there's people everywhere, some are drunk, some are looking at their phones, most of them dont ride bikes so can be assumed to be completely retarded. You are scanning, but are unable to monitor due the number of people and places they could come from. One of the retards walks right out in front, you have no time to brake, you hit them..... but you're already doing under 40 so they live.

    we've shown the survival rate graph before that show's your odds of dying go up drastically from unlucky at 40, to near certain death at about 90 or 95 depending what state you live in.... you can pretty well model it with two points and a couple of assumptions. 10% at 25mph, 90% and 30mph, and assume 0% at 0mph, and 100% at 55 or 60mph (US highway limit when the graph was produced and a year or two later when the limit changed)....... you can see those numbers are awefully pretty and convenient....... and they've been reproduced, quoted, referred to, and the graph has been fuddled with to suit agendas ever since...... take for example the fact the graph is different for nsw and victoria despite both quoting the same source, or quoting a source that quotes the same source...... there's no original thought or science since about 1971. The figures themselves might be overly specific fictitious politicised bullshit but given we can only run at about 38kph it makes total sense that we have only evolved to survive running into things at that speed...... so we can safely and honestly assume it goes up fast after that.

    cages... or crumple zones mitigate risk in the advent of an accident for vehicle passengers only. meaning that anywhere there is LIKELY to be an accident involving a vulnerable road user, impact speeds must come down to below 40kph. Take for example filtering, school zones (where kids run out) or CBD's where you can't monitor individual pedestrians.......

    ....... at this point you can see where motorbikes don't fit into the safer speeds approach......

    in speed zones higher than 60 the powers that be rely entirely on accident avoidance, whilst simultaneously spouting rhetoric against it. International testing, and our expensive duplicated ANCAP testing is only done to 64kph. Meaning above this you're in the hands of the gods even as a cage dweller. The government talks about setting limits appropriate with sight lines, traffic density, and road quality... but frankly that's bullshit because there's no requirement to use decent tyres or have minimum reflexes.... and everything else the government relies on accepts that accidents happen.... so their message is fragmented and delusional.

    If we assumed that in a car you might scrub off enough speed to get below 50kph at the time of impact, then you'd stand a good chance of survival. If you're on a bike however, an impact at 50 is serious, if not almost certainly fatal. (90% ish)

    here's a big assumption, for a hypthetical, how much speed can you scrub off? everything says its minimal, if you have time to slow a lot then you have decent sight lines and time to take other action, so at best, i'd say if you're travelling above 80kph the whole safer speeds program isn't going to help you at all.... you're relying increasingly on accident avoidance, and we see that every day. accidents that happen at 100kph rarely have good outcomes..... ditto 99kph or 101kph.... and the microseconds you save by having your eyes on the road, not the speedo, and using decent tyres more than outweighs the initial 1 or 2 kph difference you're trying to avoid because once you're on the brakes the 1kph goes quick.

    Ive thought about this because I got caught at 99 in a 50 zone OUTSIDE a town...... for a car, theres a significant safety difference, it's basically life and death..... but on a motobike, it's death and death, there's maybe a 5% difference in my odds and i'm in the range of seriously fcuked up so im not sure which is better....... speed limits just aren't made for bikes.

    I have to go, but hopefully this helps explain why suburban 50 limits, urban/school 40 limits are appropriate, but all our limits over 60 are purely driven by revenue raising.