How do I get the mobile speed camera on our road?

[spindrift]

Spindrift and his eco warrior clan can't accept that speed is not a killer, incompetency is!, usually on the part of pedestrians or the people carrier, Ford Fiesta/Focus or Vauxhall Corsa type driver.

 

Evidence please. You'll need to show the 'at fault' rates for road users, lkike I have done when I explained 95% of accidents are caused by driver error.

 

You've done quite well in that post barry, ad hominem, AND made-up facts.

 

If you hit a cyclist or pedestrian at 35mph rather than 30mph, the force of the impact increases by more than a third. This is basic science, you can look it up if you don't believe it. Probably best to look it up BEFORE you decide to drive at 40 in a 30 zone though, if only to educate yourself about the danger you are inflicting on other people.

 

A change in the mean speed of traffic will affect collision risk and each reduction in mean speed of 1mph will reduce collision frequency by about 5%, that's the robust rule mentioned upthread.

 

 

Just get out of bed earlier, stop being anti-social.

[Treatment]

Get on the square of Solomon's Temple.

[Treatment]

 

If you hit a cyclist or pedestrian at 35mph rather than 30mph, the force of the impact increases by more than a third. This is basic science, you can look it up if you don't believe it. Probably best to look it up BEFORE you decide to drive at 40 in a 30 zone though, if only to educate yourself about the danger you are inflicting on other people.

 

Isn't it E = MC Squared ?

 

(i don't know how to do a 2 for squared).

[Cyclone]

No, it would be f=ma as the basis of any calculation.

Working out the acceleration imparted is the difficult bit though.

 

It's definitely not true that the car has 1/3rd more energy, so without having worked it out intuition suggests that the accelerations involved are not 1/3rd greater.

Any formula's or a source to back it up spindrift?

 

lol - still quoting 95% driver error are we. Despite the DoT reports that show 55% of pedestrian deaths being pedestrian fault only, 24% being fault on both parties and the remaining small percentage being driver fault only.

[spindrift]

Using data from actual road crashes, scientists at the University of Adelaide estimated the relative risk of a car becoming involved in a casualty crash – a car crash in which people are killed or hospitalised – for cars travelling at or above 60 kilometres/hour. They found that the risk doubled for every 5 kilometres/hour above 60 kilometres/hour. Thus, a car travelling at 65 kilometres/hour was twice as likely to be involved in a casualty crash as one travelling at 60. For a car travelling at 70 kilometres/hour, the risk increased fourfold. For speeds below 60 kilometres/hour the likelihood of a fatal crash can be expected to be correspondingly reduced.

 

Reaction time

 

One reason for this increased risk is reaction time – the time it takes between a person perceiving a danger and reacting to it. Consider this example. Two cars of equal weight and braking ability are travelling along the same road. Car 1, travelling at 65 kilometres/hour, is overtaking Car 2, which is travelling at 60 kilometres/hour. A child on a bicycle – let's call him Sam – emerges from a driveway just as the two cars are side-by-side. The drivers both see the child at the same time and both take 1.5 seconds before they fully apply the brakes. In those few moments, Car 1 travels 27.1 metres and Car 2 travels 25.0 metres. The difference of 2.1 metres might seem relatively small, but combined with other factors it could mean the difference between life and death for Sam.

 

The figure of 1.5 seconds is the reaction time of average drivers. A driver who is distracted (eg, listening to loud music, using a mobile phone or has drunk alcohol) may take as long as 3 seconds to react.

 

Braking distance

 

The braking distance (the distance a car travels before stopping when the brakes are applied) depends on a number of variables. For example, the slope or grade of the roadway is important – a car will stop more quickly if it is going uphill because gravity will help. The frictional resistance between the road and the car's tyres is also important – a car with new tyres on a dry road will be less likely to skid and will stop more quickly than one with worn tyres on a wet road. If slope and frictional resistance are equal, the factor that has most influence on braking distance is initial speed.

 

The formula used to calculate braking distance can be derived from a general equation of physics:

 

 

 

where Vf is the final velocity, V0 is the initial velocity, a is the rate of deceleration and d is the distance travelled during deceleration. Since we know that Vf will be zero when the car has stopped, this equation can be re-written as:

 

From this we can see that braking distance is proportional to the square of the speed – which means that it increases considerably as speed increases. If we assume that a is 10 metres per second per second and assume that the road is flat and the braking systems of the two cars are equally effective, we can now calculate braking distance for cars 1 and 2 in our example. For car 1, d = 16.3 metres, while for Car 2, d = 13.9 metres.

 

http://www.science.org.au/nova/058/058key.htm

 

We need more cameras, more trafpol, more red light cameraS.

 

There are more uninsured cars in the UK (1.6m) than commuting cyclists (1m).

[spindrift]

Isn't it E = MC Squared ?

 

(i don't know how to do a 2 for squared).

 

 

Think about cars travelling at different speeds: the impact they have can be extremely different! A car travelling at 60 km per hour has four times the energy of a car travelling at 30km per hour, and a car travelling at 90 km per hour has nine times the energy of a car travelling at 30 km per hour. This is why speeding cars can be so dangerous!

 

There is an equation for calculating kinetic energy, which shows the relationship between velocity (speed), mass (weight) and energy:

 

kinetic energy = ½ mass x velocity2

 

From 50 to 75, while only a 50% increase in

speed, momentum increases 125%, which requires far longer breaking

distances and makes accidents far more dangerous.

[Treatment]

Think about cars travelling at different speeds: the impact they have can be extremely different! A car travelling at 60 km per hour has four times the energy of a car travelling at 30km per hour, and a car travelling at 90 km per hour has nine times the energy of a car travelling at 30 km per hour. This is why speeding cars can be so dangerous!

 

 

A 1 ton car doing 10 MPH has the E of 10 x 10 = 100

A 1 ton car doing 30 MPH has the E of 30 x 30 = 900

 

(900 is 9 times 100 )

 

Is my logic incorrect ?

[spindrift]

'

If you haven't run over more than 2% of the children in the country then I think we should question your grasp of statistics '

 

Tasteful use of a smiley there, you find dead children funny? Do you laugh at stories of abused children?

 

Discuss the issue, leave your 'jokes' about dead children out of it. Do you honestly think the parents of a child killed by a speeding driver are concerned with the allocation of blame?

 

Would it not be better to avoid the collision in the first place, and reduce the chances of serious injury by having lower speeds?

 

Children can be unpredictable, they do rash things. The penalty for a moment's inattention ought not be death at the hands of someone too stupid or selfish to think the law applies to them.

[Bonjon]

At least Swindon are going a step in the right direction, they covered up with a big 'not in use' bag the last of their camera's.

[DT Ralge]

Established through extensive testing I presume?

 

If you haven't run over more than 2% of the children in the country then I think we should question your grasp of statistics

 

Seriously, how is this determined. Do you ask drivers who killed children just how fast they were going? Or maybe the ones that survive, you ask the child what speed the car was travelling at?

It does make you think. Given that very few cars carry any recording device that would establish this information, I wonder who exactly made this number up.

 

 

At the scene of a fatal crash the investigating officers close the road and start off with the premise that this could be the site of an unlawful killing.

 

Their mandatory forensic analysis of the road, surface, gradient, witness statements, length of skid marks, car and tyre condition .... all help to build up a picture of what happened as objectively as they can.

 

I would not know whether it could be called absolutely scientific but years of experience and an actuarial, probability and statistical analysis of what has already happened elsewhere allows them to state in broad brush terms "hit at x mph and you survive, hit at x+10 mph it's more likely to be fatal. So that's where these figures come from - they are in no way made up. I stress "broad brush" since there's always someone who survives miraculously or someone who would normally have survived an impact but doesn't.

 

 

To back up this, there's numerous videoed tests of cars doing x, x+2,5 and x+10 mph, braking at a known point to stop the cars on their nose and a GPS clocking of the varied impact speeds. The difference made by just 2, 5 and 10 mph extra speed shocks most drivers when they watch the videos and this is in perfect road and weather conditions and the tests did not require the driver to think about braking. So the message from these is that actual impacts in the real world will always be worse than the vieoed test results, shocking as they are, and that speed doesn't kill IMPACT speed kills.

Also, because of the laws of physics, just a few mph extra makes a massive difference to the impact speed if an impact happens.

 

Such an understanding of speed and of the laws of physics should shape our choice of speed (what we think of as "appropriate") and it renders the well-worn, cliched arguments of "increase speed limits ... better brakes on modern cars ... HC figures out of date ..." largely irrelevant, missing the point and redundant since the videos show modern car performing against modern car.

 

I take issue with the authorities for missing a trick in getting the driving public on board - very few drivers have anything but a skin-deep appreciation of the subject. We nod sagely at a video showing a young girl peeling herself off the pavement. Some of the wording of the public info ads is extremely suspect. Take the snappy "hit me at 30 and I have an 80% chance of surviving."

Hell no, you cannot afford to hit a pedestrian at 30 mph without braking. Hopefully you will brake and get the impact speed down to something a lot lower. For every mph above the 30 (as an arbitrary figure) you guarantee an impact that is exponentially higher.

 

Mine's not so snappy, is it?