Safe Speed Forums

Speed humps 'bad for environment'

25/ 1/2008


THEY may be popular with residents wanting to slow traffic in their street, but research has shown speed humps are bad for the environment.

The traffic calming measure, widely used in residential areas, can increase fuel consumption by 47% on 30mph roads, a study commissioned by the AA has found.

The study, carried out by an independent engineer and car tester, found that the average car achieves 58.15 miles per gallon (mpg) at a steady speed of 30mph.

But when going over humps, it will reach only 30.85mpg.

The results were calculated by averaging the results of two cars.

It also found that cutting the speed limit from 30mph to 20mph pumps up CO2 emissions by 10%.

The research is the first in the AA's new Fuel for Thought campaign.

The motoring organisation said that it accepted that 20mph speed limits in residential areas are popular and improve safety.

But while a 20mph limit along shorter roads with junctions and roundabouts can reduce fuel consumption, a 30mph limit on local distributor roads may be more environmentally friendly.

Edmund King, the AA's president, said: "Transport and highways planners have little or no official guidance on the environmental impact of 20 mph speed limits.

"It would be a bitter and unpalatable irony if local authorities, that have targeted owners of larger vehicles with environmental charges, are found guilty of pumping up CO2 emissions through indiscriminate use of 20 mph restrictions."

Hmm.

Can somebody work out how much CO2 emmissions would go down if motorways were reduced to a strictly enforced 60mph?

If the AA was concerend about CO2 you'd think it would be calling for this.

I just don't think it is though, and this is just anti 20mph spin.

Not as much as you might think.

What IS "an average sized petrol car"? What size is the engine, how many gears does it have, is it turbocharged, etc etc "Average sized" is a meaningless measure - vehicoles with exactly the same engine size can have wilding differing performance in every respect.

Cor.

In general then, can you name a single road car than emits less CO2 at 80 mph than it does at 60mph?

The highest concentrations of Co2 are found at traffic lights. It is stop start traffic that needs the most attention.

If we are serious anout reducing polution we should opt for removing as many sets of lights, speed bumps and chicanes as possible and reducung congestion on all roads.

my car like most get better consumption at 85 than traveling round town.
Many of my journies are 25% longer than they should be because I take a longer route to avoids un-necessary humps or congestion

ie Southampton to Seven Bridge via Newbery. 107 miles rather than 70.

What IS "an average sized petrol car"? What size is the engine, how many gears does it have, is it turbocharged, etc etc "Average sized" is a meaningless measure - vehicoles with exactly the same engine size can have wilding differing performance in every respect.

the average car achieves 58.15 miles per gallon (mpg) at a steady speed of 30mph

A topical example of incidental deaths is the controversy about speed humps and their detrimental effect on the response times of the emergency services. This was brought sharply into focus earlier this year, when Sigurd Reinton, chairman of the London Ambulance Service, claimed that up to 800 victims of cardiac arrest die in London for every minute of delay, caused by traffic calming and traffic light timings aimed at deterring drivers. This compares with the 300 who die in traffic accidents in the capital each year — a figure that has not changed significantly as a result of these highway obstructions. The fire service faces similar difficulties in carrying out its life-saving duties — each road hump is said to add ten seconds to the time it takes to reach a fire or other incident

I don't think CO2 is a problem, at traffic lights or anywhere else in towns. Unburnt hydrocarbons and nitrogen oxides are more of a problem. In any case, I un-earthed this:

http://www.london.gov.uk/assembly/trans ... nsappa.pdf

Jenny Jones (AM): So you have never said that road humps cause 500 deaths?

Sigurd Reinton, Chair LAS: I do not recall saying that, no.

Lynne Featherstone (Chair): But the principle of them taking longer has to be accepted that…

Jenny Jones (AM): No, Chair, I am actually making a very important point here. We have this urban myth that the London Ambulance Service has said that they could save 500 lives a year if there were no road humps. This has now become a completely unsubstantiated myth.

Lynne Featherstone (Chair): Which he has dispelled today quite clearly.

Jenny Jones (AM): That is wonderful. Thank you very much.


I must say I'd love to see speed humps go, but we'd have to find another way of slowing some people down IMO.

(classic Brain Coleman showing near total ignorance of cycle based paramedics)

But Sir Robin Wales, of the Association of London Government, said the ambulance service should look into the impact of traffic calming on children's safety.

He said: "Our kids can not go on the roads unless there are those humps slowing traffic down."

In general then, can you name a single road car than emits less CO2 at 80 mph than it does at 60mph?

Hmm.

Can somebody work out how much CO2 emmissions would go down if motorways were reduced to a strictly enforced 60mph?

If the AA was concerend about CO2 you'd think it would be calling for this.

I just don't think it is though, and this is just anti 20mph spin.

I can confirm that my car consumes significantly less fuel at a constant 80 than it does at a constant 60. Since the carbon comes from the fuel then this will equate to less CO2 unless something really really weird is going on.

THE BIG CLIMATE CHANGE CON, REDUCE THE UK TO THIRD WORLD STATUS SO THAT MR AND MRS GREEN TWAT CAN FEEL IMPORTANT

CO2 emissions would go down if catalytic converters were removed !