I won't comment about 2) because it's been done already.

But as for 1), it was shown during early trials in the 60s that:
- people would complain about sonic booms if they were announced in advance in the media without actually flying planes
- people wouldn't complain if they hadn't been told

You can find recording on the net. Yes, it's loud but really the whole thing was more of a political manoeuvre than anything else: Sonic Boom

Because it's a scientify theory or as wiki says: A scientific theory is a well-substantiated explanation of some aspect of the natural world that is acquired through the scientific method and repeatedly tested and confirmed through observation and experimentation. As with most (if not all) forms of scientific knowledge, scientific theories are inductive in nature and aim for predictive power and explanatory force.

Meh, many small (under 2l) German diesel engines are French made (Mercedes, A and C Class -> Renault, BMW, Mini Cooper -> PSA at least until 2015 where it'll be over I think), only VW stands on its own. So it's really going to piss the French car manufacturers as well.

Poor decision making from different political camps and good lobbying by PSA and others resulted in "About 80 percent of French motorists drive diesel-powered cars." All because French were ahead of the "smoky" diesel curve back in the 80s.

But it doesn't end here: diesel at the pump should be more expensive than gas. Only a small tax break makes it cheaper.

And because we use so much diesel fuel, French refinary plants don't produce enough of it so we export our gasoline surplus (to say the US) to import diesel fuel. So even on an economical standpoint it doesn't make sense.

No idea, I was talking about the French laws.

And there's this: http://www.cafe-cba.org/assets...

Page 85, line Chronic Mortality * Premature deaths...
40000 yearly deaths based on PM

And this: http://www.researchgate.net/pu...

They estimate that every increase of 10 micrograms of particulate PM2.5 (2.5 as a 2.5 micrometer particulate) per cubic meter (g/m3) would lead to a 6% increase of death due to illness resulting from these particulates.

http://ec.europa.eu/environment/archives/cafe/general/pdf/cba_health_impact.xls

When you want to SELL.

PSA (Peugeot Citroën) marketed it first: http://en.wikipedia.org/wiki/D...

In 2000, in anticipation of the future Euro 5 regulations PSA Peugeot Citroën became the first company to make filters standard on passenger cars.

First roadworthiness check happens after 4 years for a brand new car then it's every 2 years.

http://ehp.niehs.nih.gov/wp-co...

TL;DR

For example, Rushton et al. (Rushton et al. 2012) recently estimated that occupational DEE (Diesel engine exhaust) exposure in the United Kingdom was the third most important occupational contributor to the lung cancer burden after asbestos and silica exposure.

They estimate 6% of people dying of lung cancer do die because of diesel particles...

It's not the most economical option because as people mentioned, the higher purchasing price means one needs to drive around 10000 or 12000km (that's around 6200/7500 miles) a year to get a financial benefit.

The issue here is more of the chicken and egg kind: because of the lower prices at the pump and the incentive governments have been giving away, people nowadays buy diesel because it's what everyone has or wants. When you want to use your used car, if it's not a diesel, you can forget about findind a buyer.

The issue is the particulate filters that are nowadays standards seem to be worse for your health: particles are so thin you can't see them anymore (hence no more belch smoke) but they're also so thin they can now enter your bloodstream more easily.

And modern diesel engines emit more NO2 than they used to.

So the bottom line is: invisible smoke doesn't mean it's better.

Well, I don't know how old you are or maybe your reality is really impaired but in the end, I looked it up.

I'm a 35 and I got my license when I was 18 so I was curious. It did use to 21, but that changed in 1922 (from 21 years old to 18)... ;-)

As for alcohol, you're half right: one used to be able to buy "light" stuff (cider, beer, wine) between 16 and 18 but it changed 2 years ago. Now it's 18 for everything.

You're wrong:
http://en.wikipedia.org/wiki/Fuel_efficiency#Energy_content_of_fuel
http://auto.howstuffworks.com/diesel3.htm

Your "almost identical" is something like 10%...

I'm not sure where you got your facts but they're wrong, that or I missed the irony (in which case it was funny). You can start driving only if you're at least 18 (you can have a learner permit at 16 but you cannot drive by yourself) and even if you can get away buying alcohol, legally you have to be at least 18 too (the reason why one could get away is because we don't card)...