Remember kids... always wear a helmet. (The almighty bikeradar helmet thread)

Mdcc: Dangerous in London/Britain compared with Holland or Denmark, where there are actual bike lanes separated from cars/pedestrians. Everywhere.

There are many factors involved in why crash rates in those countries are lower than here, but it's important to note that Dutch crashes have been going up and up for about the last fifteen years (by hospital admissions):

http://www.swov.nl/rapport/R-2012-09.pdf

This is despite them having built a large kilometrage of new segregated cycle tracks and it is also not attributable to more cycling (modal share has remained roughly constant and population hasn't increased sufficiently to account for the difference). As a percentage of all crashes (including other modes of transport) the percentage of injuries to cyclists has also kept going up.

The real change in safety in the Netherlands came about in the 1970s, when there was a collective change of heart and cycling both re-increased and re-acquired a higher status. As I said, there are many factors: Better driver training, different legislation, smaller, more compact cities, etc.

The real world is usually multi-causal. :)