Recently, we reported on so-called eco-towns in the U.K. which have imposed 15 mile per hour speed limits in an effort to reduce pollution. We're pretty sure that their end-goal is to remove vehicles from the roads entirely, not simply forcing them to slow down. It seems that other towns are lowering speed limits for a completely different reason: safety. The city of Portsmouth has recently become the first city in Britain to impose a 20 mile per hour speed limit for nearly every residential street, 1,200 in total.

According to the Portsmouth City Council's official website, the goal is threefold:

• to boost the safety of pedestrians and cyclists - especially children and old people
• to encourage cycling and walking
• to make streets more useable for the people who live on them

We can see the benefit to removing cars completely from the transportation equation where possible, but there is a problem in forcing cars to drive this slowly without offering an alternative, and it centers on emissions. Most any newer car has been designed to run most efficiently at a higher speeds, and pollute more when driven too slowly. Electric vehicles are less likely to encounter this problem, but we doubt that many Portsmouth residents are driving through their city in electric vehicles.

[Source: Portsmouth City Council]

There are plans in the works in the U.K. to create a new type of housing settlement called eco-towns. There are expected to be five eco-towns built by 2016, scaling up to 10 by 2020 with populations of around 5,000 to 20,000. A unique feature of these eco-towns will be the very low 15 mile per hour speed limit leading into the downtown area. The downtown will allow no cars at all.

Housing minister Caroline Flint says, "These developments will be exemplars for the rest of the world, not just the rest of the country. It's critical that we get it right - and I make no apology for setting the bar as high as possible." Flint sees public transportation, bicycling and good old fashioned walking as acceptable alternatives to driving, with a goal of cutting unnecessary car trips in half.

Not all green-leaning people are happy with the plans, though. Some believe that the resources of surrounding areas will increase due to the eco-towns while others believe that legislation is focusing in too much on transportation while leaving other important eco-issues up to the developers.

[Source: BBC, Daily Telegraph]

Yeah, the idea of lowering speed limits has been brought up before, with the intent on lowering the emissions and fuel usage by forcing people to drive slower. This would work, of course. The slower an engine turns, generally the less fuel it is using. And, generally, the less fuel that an engine is using, the less emissions are being produced.

Maybe we should propose adopting a new slower speed limit, like is being done on one street in ChangSha, China. On this street the speed limit is 5 kilometers per hour, which is just over three miles per hour. So, anything over a gentle walk is speeding. No jogging! Some motorcycles and scooters would have to be banned, because they are too difficult to control at that speed. No problem, though, just get off and walk! The world's emissions problems solved!

[Source: Weird Asia News]

What would happen if everybody obeyed the speed limit? A group in the U.K. would like to find out, assuming that there is no speed limit higher than 70 miles per hour (which, of course there is. Another topic for another story). Their website claims, and has data to back it up, that deaths would drop, emissions would drop and gas mileage would increase. And, by substantial amounts, too. I am well aware that not everybody would be willing to abide by this particular speed. I have been known to break it from time to time myself (a gross understatement? Not that I am admitting to :-). But, what about you individually? Are you willing to commit to never breaking 70 miles per hour? If so, click here and check into joining. You'll get a very stylish sticker to proudly display your intentions.

[Source: Treehugger]