Road Danger Reduction

That sort of thing doesn't need any thought given, the speed limit is literally that, if the people tend to ride right at the speed limit (says 30mph), then a 20mph one would mean motorists are likely to stick to it.

It is widely recognised that speed limits don't cause people to drive at these limits. Lower speed limits do reduce speeds, but for a 30mph limit this will mean people driving at around 30-35mph (or, indeed, lower), and similarly around 20mph (although there appears to be a particular issue with 20mph; I don't drive so can't comment, but some people tell me that 20mph sits awkwardly between two gears (is it first and second?) and drivers find it uncomfortable to drive at).

Having arrived back from Copenhagen, I realise why the particular Danish people behave as they do - not because they're danish, but because of the infrastructure and the used of the bicycles.

What I've noticed in Copenhagen is the astounding lack of motorised vehicles, in comparison to London that is, I've rarely ever seen a traffic jam that's equal to London, the people I've spoken to in Copenhagen considered a mere 7-10 cars line-up to be a "bit of a traffic jam" which amused me to no end.

because of the lack of traffic jam; those who chosen to take a motorised vehicles is no longer in a rush as they always get to their destination on time regularly.

because of the above, drivers are fairly relaxed, and are more patient when waiting at a traffic light, in London, drivers are almost always caught at a traffic jam regularly, so when they see an empty road, they tend to gun it during this small section of freedom.

incidentally the same goes to the cyclists, they're rarely ever need to slow down at lots, thus almost a lots of them waited at traffic light, even when there's no motorised vehicles to be seen at all.

I realise I went a bit off topic, but it's pretty clear of the obvious advantage of riding a bicycle, moreso, I've always talked to the car owner about how to make the most out of their cars by merely riding a bicycle, this is a win-win for me as the more I talked about the insurance they saved, the less they spend on petrol, etc. the more they can able to use their vehicles for other scenario, such as a holiday, a weekend break etc. where they'll be able to enjoy driving the cars instead of being stuck in traffic jams.
*
"That sound great! what can I do to achieve that?"

"a bicycle, it's a car's best friend"*

I don't quite understand whether you're arguing here that Copenhagen wins out because of its infrastructure or because of the other factors you cite (or all of them). Did you mean to write 'not because they're Danish, not because of the infrastructure or the use of the bicycles'? It would be interesting to hear more about your experience of Copenhagen.

It's a smaller city too (close to 2 millions people though) with 36% rode their bicycle, just that percentage make a staggering difference.

There are various figures around for Copenhagen. 36%/37% is the figure of commuting by bike, 22%/23% is the overall modal share. See:

http://hembrow.blogspot.com/2009/12/truth-about-copenhagen.html

(I believe that the statistical information in this article is correct, although there is also questionable information on this blog.)

Anyway, this doesn't really have much to do with RDR.