Lancet does brake distances

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Last updated on August 5th, 2017 at 08:13 am

The Age reports:

The risk of drivers crashing doubled if they were speeding 5 km/h over the 60 km/h limit, the Transport Accident Commission said.

Ridiculous. The TAC also claims that the “stopping distance of a car with good brakes travelling in dry road conditions” at just 50 kmh (30 mph) is 35 metres, or 115 feet.

Hmmm. This Michelin site reports 40 metre stops from 50 kmh on snow-covered roads using winter tyres; you’d expect much better than a 5-metre advantage in the dry. And a road test of the large Chevrolet Silverado reports a stopping distance from 100 kmh (60 mph) of 39 metres; only four metres further than the TAC believes is typical for a well-maintained car braking from half that speed.

Subaru’s 2002 Outback Sport is a reasonable example of a routine road machine, such as might be found on Melbourne’s streets. Its measured stopping distance is 38.7 metres – again, from 100 kmh. With rear drum brakes. What pedal are the TAC’s testers hitting?

(Much thanks to reader Blink, who raised doubt over the TAC’s claims after I’d cited them in an earlier post.)

Posted by Tim B. on 06/24/2007 at 01:51 PM
    1. On the other hand, if the car was being driven carefully and with expertise, at 65kph, then the chance of an accident would be normal. Speed(ing) kills!


      Posted by J.M. Heinrichs on 2007 06 24 at 03:08 PM • permalink


    1. I’ll admit if I’m wrong but that stop distance sounds rather long to me too.  Unless they’re talking about a leisurely slooooooow doooooown aaaannnnddddd stop.  I’m thinking more of an “about to hit a brick wall” sort of stop.

      Posted by Dash on 2007 06 24 at 03:14 PM • permalink


    1. Well, it is the Lancet after all.  They do tend to have trouble with numbers and counting.

      Posted by rbj1 on 2007 06 24 at 03:36 PM • permalink


    1. Sounds like they added reaction times in there.

      …and were drunk.

      Posted by cirby on 2007 06 24 at 03:41 PM • permalink


    1. Don’t care what they say.  Got no reason to believe ‘em about anything any more.

      Posted by RebeccaH on 2007 06 24 at 05:00 PM • permalink


    1. I have also found that when I run into the side of a bridge at @ 100 kph (62 mph) then I tend to stop immediately. Perhaps I should carry a concrete bridge with me at all times for emergency stopping purposes.

      Posted by SwampWoman on 2007 06 24 at 05:09 PM • permalink


    1. How old are their statistics?  If you’re racing your Tin Lizzie at a breakneck 50 kmh and suddenly have to hit the breaks, it probably would take 35 meters to come to a complete stop.  But nowadays they generally splurge and put brakes on all four wheels!

      Posted by Bruce Rheinstein on 2007 06 24 at 05:12 PM • permalink


    1. I read that item. So – every time I drive from a 60 zone into a 70 zone my crash risk more than doubles? I guess if the TAC says 60 it’s true; after all, look at the horrendous accident rate on our 110kmh freeways. Carnage – it must be so if the TAC say driving over 60 is as good as a death sentence.

      Posted by walterplinge on 2007 06 24 at 05:57 PM • permalink


    1. Thanks for referencing one of my comments Tim, it made my day!  (But don’t feel too special, it’s been a crappy day so far…)

      Posted by Blink on 2007 06 24 at 06:16 PM • permalink


    1. These stats are mana from heaven here in Brakistan, where the government has a love/ hate relationship with the private motor vehicle, where some media outlets decry what shocking drivers we are and where speed cameras provide another tax on the pretense of road safety. But as we are told ad nauseum and which is a crock of crap, ‘Victoria is the leader in world road safety’.
      More likely, Victoria has a primitive and superstitious distrust of private motor vehicles.
Posted by BJM on 2007 06 24 at 06:26 PM • permalink


    1. You know what this article means, don’t you?  Somewhere a Labor or Democrat pol is running for office on the braking-distance issue…

      Posted by richard mcenroe on 2007 06 24 at 06:31 PM • permalink


    1. The risk of drivers crashing doubled if they were speeding 5 km/h over the 60 km/h limit, the Transport Accident Commission said.

      But if the Little Nash Rambler is right behind, does it still have on its brake?

      Posted by richard mcenroe on 2007 06 24 at 06:33 PM • permalink


    1. TAC’s number will include reaction time. At 50KPH, a 0.4 second reaction time is about 5 meters.

      30 meters to stop at 50KPH still seems too much.

      Posted by phil_b on 2007 06 24 at 06:58 PM • permalink


    1. The TAC is the greatest fraud perpetrated on Victoria ever.  That pack of lying arseholes would make up any bullshit to justify their six figure salaries and extortion of citizens.  The sooner it’s smashed like a crab the better.

      Posted by Mr Hackenbacker on 2007 06 24 at 09:02 PM • permalink


    1. They might do better if they tried fitting their test vehicle with tyres that have a bit of tread left on them.Maybe new tyres can’t be accommdated within their budget after their salaries are covered.

      Posted by Lew on 2007 06 24 at 09:13 PM • permalink


    1. I am with Rebecca (#5) here.

      The Victorian TAC is a pack of bullshit artists, and I refuse to accept anything they have to say about road safety, speed cameras, and especially speed limits.

      There may well be some wise and helpful advice buried in their bilge, but it will never be heeded in the howling of their doomsday ranting propaganda.

      “Fool me once . . . . . . etc”

      Posted by Pedro the Ignorant on 2007 06 24 at 10:28 PM • permalink


    1. But… what if the driver is talking on their cellphone while trying to quiet the kids in the back while yelling at inconsiderate Gaia-killing SUV drivers? None of these things can be taxed directly, so I guess they’ll just have to up speeding fines.

      Posted by Jeremy Nimmo on 2007 06 24 at 10:33 PM • permalink


    1. Well, I’m surprised the Lancet didn’t report that the stopping distance was 655,000 metres.  Body counts, stopping distances….they’re all just numbers anyway, right??

      What is it about “educated” people who are so disconnected from reality, physical or otherwise?  BOTH of the local schools that my daughters attend were telling them IN OFFICIAL PA ANNOUNCEMENTS that they should encourage their parents to engage in a one-day boycott against buying gasoline.  I disabused them of that idea in a rather lively dinner conversation, after picking my jaw up from the floor.

      Posted by Tex Lovera on 2007 06 24 at 10:36 PM • permalink


    1. Next thing from TAC – a packet of cigarettes in the top pocket will add 50 metres to stopping distance of a car. Then obesity is the biggest cause of single vehicle accidents. Finally, 85% of all car accidents are the result of global warming.

      TAC is a bunch of pathetic PC bureaucrats with a limited understanding of the very subject they are supposed to administer – vehicle safety.

      Posted by Contrail on 2007 06 24 at 11:31 PM • permalink


    1. No, no, no Tex.  Lancet would *ordinarily* report that the stopping distance is between -80 and 655,000 metres, with a distance of 100,000 metres being most likely.  Statistical probabilities and epidemiological studies being what they are.

      Posted by JorgXMcKie on 2007 06 25 at 12:08 AM • permalink


    1. #19, spot on. I’ve found that bureaucrats in the vehicle safety area are some of the biggest politically correct, safety nazi fanatics you will ever come across (and that’s saying something).

      Posted by Art Vandelay on 2007 06 25 at 01:19 AM • permalink


    1. It is amazing how in a real life emergency stop, when you stomp on the anchors and the ABS Shudder starts that your heart rate hits the same cadence in half a second.  Pulling over and having a chuck when you realise how little you missed the kid on the bike by is strangely one of the better feelings in the world.

      35 meters?  Granny just had a hip replacement before the test???  I had a sore ankle I hit the pedal that hard!!

      Posted by Razor on 2007 06 25 at 01:35 AM • permalink


    1. It’s bollocks.

      I went on one of those advanced driving courses a few years ago where you take your car out on a skid pan all day with some very good instructors.

      The first thing we did was braking in the dry in a straight line at 60km/h.  My lumpen Discovery managed to pull up in a shorter distance than that (I forget what it was exactly) thanks largely to ABS and the tyres being pumped up more solidly than what the manufacturer recommends.

      The only vehicle that took forever to pull up was one in which the ditzy driver had neglected to put any air in the tyres.  They were all running at about 10psi.

      When this was pointed out to her (after she took about 100 metres to stop – almost ran off the back of the race track into the grass), she said, and I quote, “I’ll have to tell the mechanics back at (bread company name deleted) to put on new tyres”.

      When we told her about the free air hose at all petrol stations, and what it was designed for, she was rather amazed.

      Quite a few drivers fouled up their initial braking test because they had never stomped on the brake pedal before, and felt the ABS in action.  When the pedal starting vibrating, they backed off.

      Posted by mr creosote on 2007 06 25 at 01:47 AM • permalink


      Is that an oxymoron or are the ‘friends’ morons who steal oxygen?

      Posted by Bonmot on 2007 06 25 at 01:55 AM • permalink


    1. #17

      But… what if the driver is talking on their cellphone while trying to quiet the kids in the back while yelling at inconsiderate Gaia-killing SUV drivers?

      Mazda CX-7
      Stopping distance from 96.5 km/h = 33.5 metres


      Posted by BIWOZ on 2007 06 25 at 02:29 AM • permalink


    1. I think there is quite a bit of evidence and argument to suggest that this is incorrect. See:

      Basically the physics (given my limited knowledge of this stuff) suggest that impacts at higher speeds will have proportionately bigger impacts (impacts proportional to velocity squared), slower reaction times, increased difficulty of stopping etc.

      At least one study I found supported the first claim you reject.

      Posted by on 2007 06 25 at 03:17 AM • permalink


    1. I once looked up the figures for the number of road deaths in the UK and divided it by the population there and the ratio was roughly the same as the ratio I calculated for Victoria. Yet in the UK all speed cameras are required to be painted yellow AND have to be sign posted as you approach them AND have to be located on a stretch of road that has had a high number of fatalities (ie: they just want you to slow down where it’s dangerous).
      Also, in the US, as reported here, speed limits were raised to up to 80mph in some states and the road toll went down.

      Posted by Zuzzy on 2007 06 25 at 04:37 AM • permalink


    1. My poor speed-deprived Ozzie friends. I will think of you fondly whilst I’m hurtling down the autobahn at 210kph.

      Posted by Texas Bob on 2007 06 25 at 04:57 AM • permalink


    1. …(impacts proportional to velocity squared)…

      Unless your car is travelling at near-light speeds the rule is:

      force = mass x (velocityDelta / timeDelta)

      …NOT velocity squared.

      Posted by Craig Mc on 2007 06 25 at 05:30 AM • permalink


  1. It’s not just TAC. Lots of things don’t make sense when examined on the Oz roads fronts.

    .Until the (mid?) ‘70s, NSW had prima facie speed limits. When changed to 100k limits by the Wran gov, no sudden decrease in road deaths, yet the new limits (and speed fine revenue) stayed.

    .German autobahns had no speed limit, yet no accident mayhem either!

    .Europe in general has more traffic, and in general, higher (eg 130k) speed limits than oz. Again, no substantial mayhem either (of the type TAC warns would happen).

    A US state (Montana)
    a period of open speed limits with interesting results;
    “For the last 5 months of no daytime limits in Montana… reported fatal accident rate declined to a record low”.

    And NT just changed from it’s prima facie (ie NO) speed limit. Doesn’t seem to have drastically improved things there either.

    Dual carriageways /decent roads will save more lives than any number of speed traps.
    trouble is, good roads cost maoney.
    Speed cameras raise money. So which do our rulers go for? And why?

    Posted by Philbert on 2007 06 25 at 07:15 AM • permalink