Think Rachael is right here.
Any objections to me splitting off the posts which are debating the limits in general? I’d propose making a new topic, “The 20mph Debate - 2017 Edition,” which linked to the old debate, and to this one.
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Personally I think the two topics are so interlinked youll never have one without the other. Leave it.
That’s a straw man, isn’t it? My own view (based on experience) is that the danger is increased for other drivers. Saying that, it’s probably better for pedestrians.
Happy to accept your data about little difference between 20 and 30 on the basis that the source looks good. Good point.
No, someone just said it.
Matching one biased source with another for balance.
http://www.rospa.com/road-safety/advice/drivers/speed/20mph-zones-and-limits/
I’ve been to a briefing on London road infrastructure where TfL advised the Mayor’s plan (current and past) to convert automobile journets to other modes of transport. They estimate as much as 4/5ths of private car journeys are unnecessary and simply put London’s roads are already at full capacity. Less car journeys less missions. Higher co2 compensated for. The suggestion that beyond road safety the 20mph which the Mayor’s office supports is part if an overall strategy to significanty change the mix of transport modes. I’ll try to find my notes and share with you. It was fascinating.
Genuine question. Any physicists/chemists here? A litre of unleaded weighs less than a litre of water. In rough figures call it 0.75kg.
So how does 0.75kg of unleaded produce three times its own mass - 2.36kg - of CO2?
It takes 5,000-20,000 litres of water to produce 1kg of meat.
I guess the fuel statistic took into account the whole lifecycle?
??? That’s MORE water producing LESS meat - which makes sense. How does less become more?
The production and transportation of petrol produces CO2.
Ah. Yes, I see what you mean, now. That’s not how I read the data but I guess that could be the answer.
“The amount of carbon dioxide (CO2) that is produced from burning a fuel weighs more than the amount of the fuel itself, because during complete combustion, each carbon atom in the fuel combines with two oxygen atoms in the air to make CO2. The addition of two oxygen atoms to each carbon atom forms CO2, which has an atomic weight of 44—roughly 3.6667 times the atomic weight of the carbon, which is 12.”
Got it! Thank you! So it’s the combination of the mass of the petrol and some quantity of mass of air in which it combusts that produces ‘more’ CO2.
Thanks, @Foresthillnick!!
Phew guys what’s that in sweetie weight, gases etc 
In other words, the only changes are likely to apply to the worst offenders and only then when they land in court?
In other news: Telegraph newspaper guilty of click-bait headlines… (see OP)
20 mph is just a joke if I put my car in 4th gear take my feet off the accelerator my car will do 27mph the roads are for everyone but in saying that we all have a duty of road safety pedestrians need to cross in the right place not just walk out in between parked cars cyclists need to obey the highway code and hopefully the roads will be a safe place for everyone
Sounds like your car is in urgent need of a mechanic or taken off the road.
I think the blanket introduction of a 20mph across all roads in the borough, excluding the TFL roads is the issue. I have no problem with our narrow, residential streets being 20mph - when there’s only room for one car due to parking 30mph does seem excessive. But to roll this out on roads such as Perry Hill, Sydenham Hill etc just leads to driver frustration and ultimately people ignoring the limits.
Not really the case. Most cars will keep themselves idling at about 800-1200rpm, if you slowly release the clutch on a manual car, it will increase the speed to maintain engine speed, therefore accelerate. I do the same with my BMW when in traffic.
I totally agree that cyclists need to sort themselves out. As a keen cyclist myself, I now find myself shouting soft abuse at riders who ignore signs, lights etc.
Everyone “sharing” the roads needs to do their bit.