1 May 2007

Eye witness account of the cycling accident.

| johnboy
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mcjimminy has posted an eyewitness account of the accident on the Cotter Road on the weekend which I thought was worthy of wider exposure and consideration:

Well, I was unfortunate enough to be an eye-witness, as I was stuck near the front of the conga-line of civilian Cotter goers. So, I have some facts as well speculation and opinions.

Facts first (well, my recollection of what I saw). We came across the race just as the group was taking off from near Duffy. There were many signs and marshals, and from what I remember, two lead cars to warn oncoming traffic, and two chase cars just behind the main group. As the only alternate route to the Cotter from there would have been via Tuggeranong, we just sighed “oh well” and joined the slow queue to the Cotter. We were doing around 20km/h on the flat stuff past Mt Stromlo, and then maybe touching around 60km/h on a descent before slowing back down to maybe 30km/h as it flattened out. I remember thinking that they were doing well to stay on the left, as I hadn’t seen anyone come across the lines, and I don’t recall having seen any traffic coming the other way at all. I then saw one rider swerve right, far out onto the wrong side of the road, I may have seen another come just a little way out. The rider that was way out was looking backwards over her left shoulder, I thought it was an overtaking maneuver, but touching wheels would also explain it. She was now still a long way out, obviously in control of the bike and riding straight ahead, but still looking backwards over her left shoulder. I then heard the squeal tyres and saw the oncoming vehicle. He was totally locked up and slowing very rapidly. At the same time, I saw the rider look forwards, and then jink left desperately to try and avoid the vehicle. She didn’t quite make it, and took a big impact from the right front of the vehicle. She had moved left enough with the last-second jink to be thrown back and left (rather than directly back or under the vehicle) and into the rest of the pack, bringing them down hard. My view of the road on the other side of the centre line was clear, my view of the main pack directly ahead was not. I saw no riders down until the rider on the wrong side of the road was hit and thrown into the pack. I saw no other rider impact the car.

Some speculation and opinions. It looked to me like the driver of the vehicle was already moving at a much reduced speed (probably because he had already come past the lead cars and front runners), as it was a big heavy vehicle and it still seemed to pull up quickly. As someone else pointed out, riding into a wall at ‘only’ 20km/h is still going to mess you up. The driver was totally hung out to dry: from his direction it was a blind right hander, and he had nowhere to go. His quick reflexes, and heavy brake foot (a locked up car slows quickest, and there was really no room to swerve around), and the belated left jink of the cyclist probably saved her life. The 4WD in question appeared to be a working vehicle (perhaps from a rural property), it wasn’t a shiny school-running prado/lexus/volvo/bmw/whatever, though of course even it was, they would still have every right in the world to be driving in a reasonable fashion on their side of the road. From what I could see, the poor driver was also the quickest out of a car and on the phone calling for assistance.

I understand that crossing a double unbroken line with your vehicle is a traffic violation. I also believe that when on the road, a bicycle must adhere to the road rules. On many occasions I’ve come across cyclists riding two or more abreast who seem to think it would be better for me to cross a double unbroken line on a bend around which I can’t see (hence the lines), or continue behind them indefinitely at a much reduced pace (hoping I don’t get rear-ended due to massive speed differentials), than for them to move over to the left to let me go past safely. I can’t understand the dangerous, selfish, inconsideration of the moving road-blockers. Of course as with anything, there are the majority who do the right thing, and the few who bring the rest into disrepute, but there you go. I’m a pretty keen cyclist also BTW, and I ride single file when riding with others. I think it’s not only for the consideration of other road users (though I rate that highly), but a personal safety issue. If the nature of a race event on an open road means that it cannot be guaranteed (or even be likely) that riders will (willingly or otherwise) stay on their own side of the road at all times, then such a race isn’t viable.

And some more opinions. Road closures would have made the event a reasonable proposition from a cyclists safety point of view, but would not provide a fair go for the rest of the population. If the location means that a reasonable alternate route can be provided, then fair-enough–for example, when they close the road around Lake Burley Griffin for the triathlons you can detour through Yarralumla without much hassle. But removing access to the Cotter Reserve and the Brindabellas on a weekend?!? Maybe Sard thinks it’s ‘cycling world’ out there, but the rest of us thought it was a public road that’s the only way to get to popular locations in the ranges west of the city.

Obviously you’d hope that no one pays such a price for a mistake (whomever’s it may be), and I wish everyone a speedy recovery from all the physical and mental trauma.

Comment by mcjimminy — 1 May, 2007 @ 11:31 am

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The tractor in that scenario has one other major advantage – visibility.

OK TimC I’ll admit to exaggerating about the threat of being rear-ended if you admit that it’s going to be safer (for cyclist, overtaker, and any oncoming traffic) for a car to go past a cyclist who’s over on the left than one in the middle of the lane.

You may well be moving a lot faster than a tractor, but it’s a safe bet that you’ll be going a lot slower than a car. If ‘vehicular cycling’ has you impassable in the middle of a winding country road, then you are suggesting that everyone will just have to proceed at your pace until a rare overtaking opportunity arises. Often those tractor drivers will pull over regularly to let the queue of faster vehicles go past. When I’m driving I’ll move over into a turnout to let cars that are obviously travelling faster than me go past. I just think it’s polite consideration, prevents frustration and aggro, and it’s not much hassle. When I’m being overtaken on a two-way road I slow a little and move to the left a little, reducing the time that the other vehicle needs to be on the other side, and giving them plenty of room when they come back over. There are those signs on the highway too, ‘keep left unless overtaking’. It’s all about letting faster vehicles go past in the safest way.

I’m all for a cyclist owning the road as they make a well signalled turn in the city. I think it makes it clear to the traffic what they’re doing, and prevents cars from thinking that they might be able to squeeze past on the inside or something crazy. I don’t think that this translates to a country road scenario.

I’m sure that you think that your average speed or PB lap time is important, and I probably weigh too much on my right to proceed to where I’m going at somewhat closer to the legal speed limit, but we’re still just sharing the road. Let’s share nicely.

“it’s pretty much ‘cycling world’ out there and so if anyone belongs out there it’s cyclists,” Tanya Sard told ABC Radio.

*THIS* is the sort of arrogant attitude which brings hatred towards cyclists. What happened to the attitude of ‘sharing the road’?

“The issue we’ll have to consider further down the track is whether due to the fantastic participation number we’ve got in this race, whether or not we can close the road, and that’s something we will consider and work with the local government on that.”

Sounds like Tanya Sard has a guilty conscience. As well she might with the blood on her hands of the injured rider.

On many occasions I’ve come across cyclists riding two or more abreast who seem to think it would be better for me to cross a double unbroken line on a bend around which I can’t see (hence the lines), or continue behind them indefinitely at a much reduced pace (hoping I don’t get rear-ended due to massive speed differentials), than for them to move over to the left to let me go past safely. I can’t understand the dangerous, selfish, inconsideration of the moving road-blockers.

But you are saying you would be able to overtake riders if they were in single file on a windey road without crossing the double white lines around blind corners at all?

Not on any of the single lane windey roads I’ve ever seen. I’d rather ride in the middle lane of the road when I can ensure that no motorist gets the stupid idea of side swiping me and forcing me into rocks on the side of the road (I’d encourage you to ride about vehicular cycling if you’ve never heard of it before).

I’m riding a heck of a lot faster than tractors that drive on the road around here, and you sure as hell are not going to abuse a tractor driver because they are stopping you from overtaking around blind corners.

And why would you get rear ended for driving slow? Hopefully everyone else on the road is a competant driver and doesn’t exceed a speed that will allow them to stop in time for the vision they have. Hate for them to encounter a downed tree, fallen rock or recently broken down truck around that blind corner of yours.

Well, there’s some detailed maths here http://hypertextbook.com/physics/mechanics/friction/ that indicates that on a dry road ABS will use 90% of the distance of locked up brakes. Also, a well written piece here http://www.iihs.org/research/qanda/antilock.html states:

“Adequate braking is easy to achieve on dry roads with or without antilock brakes. Even if wheels lock, the coefficient of friction between tires and road surface still is relatively high, so a vehicle stops relatively quickly.”

Though they don’t cite a reference in support of that statement.

It seems that on dry ashpalt, ABS will pull you up shorter, but not that much shorter. The main intention of ABS is to maintain steering control.

jemmy’s straightened me out though. It’s all about Joe Public reducing the impact energy of an unavoidable collision, by acting as quickly as possible. The time you save by simply jumping on the pedal as quick and hard as you can, outweighs the disadvantage of the reduced co-efficient of friction of skidding tyres (again, assuming the collision is unavoidable).

If they are going to start work on installing a bike lane on the Cotter Road & Uriarra Crossing area, that means that people who use those roads in a diversion to avoid the glenloch interchange will have to deal with roadworks, whilst trying to avoid roadworks.

Actually, forget my reference to FG & Vader. For some reason, I thought they were arguing against my previous post. Sorry, guys!

FG & Vader are right in terms of physics and best possible, but I don’t think that’s what we’re talking about. We’re talking about the shortest distance (or, minimum kinetic energy at impact) to stop given an unanticipated signal. While the racers are mucking around manipulating the pedal to get it to the lock-up point, the car is still travelling at high speed. The novice who just hit the brakes hard has already slowed the car significantly. The most important thing is reduction per unit of time. It’s crucial to get as much speed as possible off in that *first* unit of time.

Don’t forget distance travelled at high speed is much more per unit time (obviously, duh), and kinetic energy is squared. Take just 20kmh off, and you’re already in a much safer place. We’re not talking about seeing who can do it the shortest distance, the distance is already given, it’s the obstacle. We’re talking about impacting that obstacle that is a given, it’s already there, at say 25 metres, with the least kinetic energy. In that situation, the most important thing is get rid of kinetic energy as quickly as you can, since it’s a square root reduction, given that you only have say 2 seconds to impact, you don’t want to waste 0.5 seconds fine-tuning your braking pressure.

They did a similar test to this on the awful “Last Chance Learners” on Ch7 last week.

The idea was for the learners to drive at 80kph then attempt to stop in the minimum possible distance once passing a certain point.

It was stated before they commenced that an average driver, with ABS assisted braking, should be able to stop in around 28m.

All but one of the learners locked up the brakes (the producers had disabled the ABS systems). The girl who didn’t lock the brakes stopped in around 28m, as per the previous discussion. None of the remainder managed to stop in under 40m.

There are good reasons why locking up the brakes takes a greater distance to stop. If you really want I could give you a physics lesson, but at the end of the day all you really need to know is that hard braking will stop you in around 30% less distance than locking the brakes and sliding to a halt in a puff of tyre smoke.

I can and have proved that hard braking is better then locking up. How?

I have one these groovy little devices http://www.gtechpro.com/ Basically it’s a triaxial accelerometer. It measures the lateral G-forces on the car and gives you various readings. Including HP, 0-100km times, 1/4 mile times and wait for it! Braking distances. It’s accurate to +-.01 seconds in timing mode and +-1% in other modes. That seems pretty accurate to me. I haven’t done a braking test in quite few years now as it’s pretty hard on the car & almost destroys the tyres, but the last time I did it we used an 85’ Pulsar ET Turbo & a 93’ Pulsar SSS with ABS. I can’t remember the exact figures but I remember that the ET stopped about 10 or so meters shorter under hard braking then locking up. We were also able to pull the SSS up several meters shorter under hard braking then the ABS. Yes we out braked the ABS system. Mind you early ABS wasn’t that fantastic and I’d like to repeat the test with a modern ABS car. I’d bet the ABS could pull the car up just as quick now.

Anyone with a modern ABS equipped car want to volunteer for a test?

Ok, I’m a hoon!

FWIW, I have a lot of experience on gravel with rallying in WA, but no experience on tracks or road. I did a one-on-one driving course when younger and a hoon, in a pretty advanced sporty car without ABS. The instructor demonstrated locked and unlocked braking on dry bitumen and on gravel. He was able to convince a very sceptical me that locking it up is best, up to a point.

On dry road in normal circumstances, an untrained driver (i.e. a driver who isn’t a competitor) in a modern car at legal speeds will stop in the shortest distance by simply applying the brakes as hard as they can. The reason is simply reaction time. An untrained driver will not apply the brakes correctly and will waste time manipulating them. He would have been better off getting rid of that kinetic energy by immediately applying very hard braking.

For drivers with motivation to practice, Ellingly above is right, the best way is to brake hard to get the weight on the front wheels and to allow the front-rear bias-valve to take up its adjustment, and then to literally stand on the brake pedal. You would be absolutely amazed at how short you can stop without locking. The G force was so great that I was out of my seat and held back by the seatbelts and I was, as I say, literally standing on the brake pedal.

For gravel, it’s a no-brainer. Just stand on the pedal. The locked tyre digs a ditch and the gravel builds up in front of the wheels to give a sort of up-hill effect and slowing the vehicle very quickly.

Nowadays with ABS, it’s all moot. The hardest thing I find is overcoming the training of my youth and not trying to manipulate the pedal, just stand on it as hard as possible.

Ahem, I did mention “On a dry road”.

OpenYourMind10:44 pm 01 May 07

And here’s a physics site that looks at stopping distances: http://hyperphysics.phy-astr.gsu.edu/hbase/crstp.html
Interestingly, it indicates that on a dry surface the difference between locked and hard stopping was not apparent. Locking is not so good for the tyres though!

OpenYourMind10:32 pm 01 May 07

When I was younger and sillier, I discussed this with a friend in the context of locked wheels in the dirt stops quicker than hard braking. Even then we knew that on tar hard braking at near lock up is best. We decided to put it to the test in his mum’s Laser. The dirt was much harsher than we expected on a locked tyre and we flat spotted it. Scientific results were inconclusive and his mum was p1ssed off!

A car takes much longer to stop when the wheels are locked. Reason why is locked wheels slow down the car less quickly because the braking surface is the tar and a film of molten rubber where the tire contacts it, rather than carefully-engineered brake pads and brake discs. This is far more apparent in the wet, where once lock-up occurs, the water is simply allowing the locked wheel to glide over the road surface.
I may be a strong cycling advocate, but I had a hoon upbringing and used to hill climb cars, dirt bike ride and ride sports motorcycles.

sounds like a job for mythbusters

or does anyone want to organise a trial?

A locked up car does NOT slow quickest!!! This is why ABS stops a car more quickly by allowing the wheels to maintain traction near the brink of skidding.

Utter *nonsense* based on sales-pitch hype. (I have a large bridge for sale if you’re interested…..)

On a dry road, locked wheels result in the shortest braking distance. However – locked wheels also means minimal/no steering control, which is the trade off.

A tragic accident during a sporting event is what needs to be focussed on here. The question of leaving the road open or closing it during such an event needs to be resolved. To broaden the discussion to cyclists’ perceived bad habits in urban Canberra is bizarre.


I appreciate your argument. Certainly there are European countries where pushies are king. Certainly there is a less than glorious future for oil.

But I am less than convinced that pushbike riding will save the planet. As I have said, this will be a very hard sell to the vast majority. I contend that any wholesale shift to pushbike riding by a proportion of the populace will result in a (disproportionately) high increase in accident/injury/fatality rate for riders. Good grief, we whinge about P plate drivers, how do we account for any misadventure by inexperienced pushy riders?

I am unsure that we are ready for a total change of mindset to encompass the inclusion of a pushbike riding culture. It will take years for this to take hold, because there is no immediate, overwhelming reason to believe that pushbike riding is any answer to the problems we are currently facing as the ratepayers of the ACT.

OpenYourMind7:56 pm 01 May 07

Well, Cranky, you don’t need that much of a shift in things to change that. My workplace has a roughly 25% level of participation (120 staff). I’ve been to places in Europe (cold places too) where cycling is embraced.
Here’s another very strong argument. Australias oil supply is in decline. We are now using 800k barrels a day and only producing 600k. America was a net oil exporter and now only produces 5mil barrels a day and consumes 21mbd. That 16mil difference has to be made up. (Reference BP Oil Report- see previous link). Consumption increasing and production declining is not a good situation.
There are alternatives, but none compete with oil for one reason or another. We don’t need to get that many people on to bikes to make a difference.
The incentive of promoting cycling really isn’t costly, Cranky, the alternative is.
In terms of danger, cars are the shocker. As I’ve said in previous posts, the costs of motor vehicle road trauma exceed all the fees/taxes and rego that you pay on your motor vehicle.

This has to be a ‘Chicken and Egg’ arguement.

Or a ‘Build it and They Will Come’

When pushbikes reach plague proportions, perhaps we can open the coffers to pander for this breed of citizen. However, should we be funding a very small proportion of the population to fulfill their idealistic goals?

Push bike riding will only ever be attractive to the few. Providing Rolls Royce facilities/road conditions is unlikely to attract a quantum leap in useage. For heavens sake, it is a bloody dangerous pastime for a start! And that’s just on health grounds, without mixing it with motorists.

So should we be providing the (costly) incentive to attract people to push bike riding, or, as in every other aspect of Government, reacting to a need?

Conservation Council is calling for no registration of bikes as it would mean less people would take-up cycling. Also crashes from bikes are not that serious:


OpenYourMind6:45 pm 01 May 07

Commuting to the new suburb sounds logical for a cycling lane. In fact all new roads should include a cycling lane. It costs very little extra and is of huge benefit to the community – same as footpaths. But retrofitting to the cotter for recreational cycling doesn’t make sense to me (and I am a regular recreational rider of the Cotter area).

It’s strongly in the interest of the Govt to aim for maximum takeup of commuter cycling for all the obvious reasons – less smog, less road wear and tear, less traffic & parking hassles, less CO2 emissions, healthier population etc. etc.

For riding to Stromlo Park and commuting to the new suburb, not relevant to racing. Accurate as any other news report!

The long course on Sunday also went out through the Cotter, through Tharwa, to Honeysuckle Creek. Hard to close all of it.

captainwhorebags6:34 pm 01 May 07

I applaud the ACT Cycling group for their call and wish them well in their efforts in raising the necessary funds to widen the road and add a cycling path.

That’s going to be some real money.

The ACT Cycling group has now called for the Cotter Road to be widened and a bike lane placed along it to cater for the racing cycling community. Saw it on WIn just now.

mcjimminy – it’s a common mistake, but locking up your wheels bleeds off less kinetic energy than disappating it through the brakes (which is what happens when your wheels aren’t locked).

If you got the most efficient transfer of kinetic energy to other energy (which is what slows you down) then doing a burnout would be the fastest way to take off. Which it isn’t.

Maximum grip by a tyre is given by about 5% slip, the problem is, 5% slip when braking tends to start it locking up, which unless you do proper threshold braking, will persist with locked brakes.

ABS lets you steer around obstacles, yes, it also doesn’t defeat the laws of physics. On a dry road, it’s about as efficient as someone well trained in how to emergency brake. On a gravel road, it sometimes isn’t the most efficient, but we’re talking 1-2m extra, at 80km/h, which is offset by the extra ability to swerve (significantly harder without ABS on gravel than most people realise!).

The secret to stopping hard is to get you extra traction on the front, using weight transfer. You start off braking hard, and you just keep on laying on the pedal. You’d be surprised just how much extra braking effort you can put in. If you lock up the wheels, not only do you have less traction cause the tyres are sliding, but you also have less force pressing down, providing you less traction.

I don’t have any online references for this, but it’s in numerous advanced driving manuals… which I’ll cite when I’ve moved house.

Got the ABS comment in the old thread too. My response is:

I’m not sure that you’re right. I thought ABS was designed primarily to allow the driver to steer around the obstacle to avoid a collision, as locked up wheels can’t steer–a matter of control (and even tyre wear). Absolute stopping distance is a different issue. I may well be wrong, and it would definitely depend on conditions (wet, dry, gravel etc). Google doesn’t turn up much regarding absolute stopping distance on a dry road. I’m interested to know though, and happy to learn more from a reference to a study or something–not that I can turn the ABS off, or would want to. I do remember reading somewhere also that often people don’t press hard enough on the brakes in an emergency situation, which is why manufacturers are starting to put in sensors to detect emergency braking and automatically engage the brakes as hard as possible (though in conjunction with ABS). Anyway, that’ll learn me, even though that bit was with the speculation/opinion.

Regarding alternate routes. It was my impression that the route did include the Uriarra road as well–providing a loop back to the starting point. If this course was closed, then the only way to access the Cotter and Tidbinbilla would be south via Point Hut Crossing (which you may well only discover after you get near Duffy, making for more than a 48km backtrack and detour if you were off to the Cotter), and you’d be pretty much screwed if you’d planned on heading anywhere up the Brindabella road like to Mt Franklin, Mt Coree, Blundell’s Flat, the Brindabella Valley etc.

For what its worth, a reasonable detour to the Cotter would be via Uriarra Crossing. Not ideal, but much quicker than the Tuggeranong route mentioned by the author.

Actually, from what other people said, it is my understanding that the racing went along Brindabella Road, which would mean that there would be no access from Uriarra Crossing to Cotter. The only sealed road access to Cotter would be from the South, via Point Hut Crossing (since there is no bridge at Tharwa…)

I just wanted to clarify that I was pointing out a factual error, and not trying to lay any blame for skidding to the driver.

If you drive on the parkway in the morning on a regular basis, it’s clear that when in an emergency braking situation most people lock up thier tires.

“and heavy brake foot (a locked up car slows quickest, “

A locked up car does NOT slow quickest!!! This is why ABS stops a car more quickly by allowing the wheels to maintain traction near the brink of skidding.

Thanks for that, mcjimminy. Nice to read an account that isn’t soured by emotive language and finger-pointing.

For what its worth, a reasonable detour to the Cotter would be via Uriarra Crossing. Not ideal, but much quicker than the Tuggeranong route mentioned by the author.

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