It's not just about enforcing the law on dangerous driving, the mindset of almost every motorist on the roads needs to be changed.
For example the 20 mph speed limits. There's no point introducing them without enforcement (which the met have said they're not interested in) because they're almost completely ignored, or just regarded as advisory. This is even to the extent that although it's possible to comfortably exceed them on a bike, you still get motorists driving up your arse or aggressively overtaking - with a bit of abuse thrown in for good measure - because you're somehow holding them up.
^ this