Now I think you are trolling rather than making a serious contribution to the debate. Trolling is unwelcome here and can result in the suspension of your user account.
Munchgreeble wrote:
I stopped at the very start of your 12mph page because the whole foundation of the argument is unsound - there seemed no point in continue. However, the argument continues to become more illogical so that the end conclusion is just plain ridiculous.
This is how I know you are trolling. Clearly you didn't 'stop at the start', and it's utterly bizarre to dismiss an argument without considering it as a whole.
Munchgreeble wrote:
I'm not going to spend any more time illustrating that the foundation is bogus, but let me just tackle a couple of points that the argument goes to next.
Munchgreeble wrote:
1. You are keen to separate free travel speed and delta V as two separate concerns, yet when you reach your conclusion you suddenly forget this distinction and declare that a calculated delta v of 12mph indicates that the speed limit should be 12mph! As you yourself said in your last post, "average impact speeds are tiny in relation to free travelling speeds". In fact, since even the worst drivers brake before a collision this really is common sense - who in their right mind would set the speed limit based on the assumption that nobody uses the brakes??!! Do you see how ludicrous the argument sounds?
The 'ludicrous' argument is EXACTLY the argument that the authorities are using. The purpose of the page is to illustrate and quantify it's absurdity.
Munchgreeble wrote:
2. You again mix up the population mean with the population distribution. Supposing all the argumentation so far were in fact correct - the tying up of the population mean with a single point on the graph, the assumption that drivers never use breaks (and that that's how speed limits are set) etc. we now come to a startling revalation - dispite the fact that your graph in figure 2 shows an extreme bias in ratio of fatalities towards the top end of the graph, you seem to think that limiting the speed to the mean will have no effect. Let's go back to our example of the dice. What you're saying is, if we dissallow any rolls of the dice higher than the mean (3.5) that it will have no effect on the mean. That is, you reckon if we disallow 4, 5 and 6 to be thrown, then it won't lower the average from 3.5. Of course it will! If you had an average of 12mph that means some higher speed impacts and some lower speed impacts balance out at an average of 12mph. Getting rid of the stuff above 12mph (or 30 or whatever speed you want to pick) only leaves the stuff below 12mph - which certainly doesn't have an average of 12mph - or do you think that these imaginary people who never use their brakes always travel at a fixed speed of 12mph?
We're properly looking at real world average results. The facts are there.
Munchgreeble wrote:
If you present arguments like this to back up your case, you could easily be written off as "not serious" and trying to "fabricate" reasoning to back up your point of view. If you really do have hard scientific evidence that enforcing speed limits doesn't reduce road deaths then focus on that (I suspect you have other pages which cover this like I say I'm not a regular reader). Don't undermine your case by peddling arguments that sound persuasive to Joe public, but actually make no sense.
You're wrong in your claim that the argument makes no sense. There are limited opportunities to characterise the operation of our road safety systems in the real world. This page takes a useful view of real world data that illustrates the vital contribution of driver behaviour.
Munchgreeble wrote:
Now for some hard physics. As I suspect you know, the amount of energy in a moving vehicle is half of it's weight (mass) mutiplied by it's speed and multiplied by it's speed again (0.5mv^2). That is to say, if you're going say 50% faster (e.g. 30mph instead of 20mph) there is more than double the energy in your car. The amount of time you have to react to a given situation is cut by 50% and therefore the amount of time you have to take preventative action is cut still further. When you do react, you are less able to turn to avoid impact and have a much longer stopping distance. Finally, if and when you do have an impact, all these factors add up to making an impact speed way higher than the 50% difference you started ot with, causing a much worse accident than at the slower speed. In fact in a lot of cases, if you're just travelling slower your reactions, evasive action etc. will be enough to avoid an accident completely, that, at a higher speed would have been unavoidable. Clearly 50% is fairly extreme, but the same is true to a lesser extent with any speed difference.
And as this page shows, it's clearly not the speed limit that enables us to mitigate the kinetic energy of vehicle movement. It's drivers responding to hazards.
Munchgreeble wrote:
No matter how good your road sense, reactions, vehicle brakes etc. they don't get better the faster you go. You will almost always be able to handle a potential collision less easily than if you are going slower. The only time speed is an advantage is if you're facing a side impact or some similar where you need speed to get you out of the way in time.
That claim is absolute rubbish. Dsrivers must slow in response to hazards. Time to react is not a function of speed, but something that drivers routinely create by appropriate early response to hazards.
Munchgreeble wrote:
These are the kinds of basic issues you're going to have to tackle to convince people like me. If you have a good argument against such basic laws of physics then I'd be glad to hear it. Personally, since driver reactions don't increase with vehicle speed, and since ability to correct the vehicle's trajectory goes down as speed increases, I'll be very surprised if there is such an argument, but I'm willing to hear it if there is one. Just one plea, if you don't have a real argument to present, please don't try to dress it up with scientific sounding words when the basic argument doesn't hold water!
It holds excellent water, thanks.
Munchgreeble wrote:
I guess this must be hard to hear, but hopefully you'll end up with a more solid case to present at the end of the day. And for what it's worth, whilst that particular argument leaves me rather nonplussed, I like the approach you're taking of trying to get to the heart of what causes accidents and encouraging safe driving.
Spoken like a true troll.