Its such a problem that if you investigate cycling deaths, the biggest hotspot is literally a roundabout in the center of Oxford outside a college. By hotspot I mean , its literally the number one most dangerous location ( about a 10 meter stretch) for cyclists in about a 50 mile radius. I discovered this one day just doing some random research on my own.
Also unfortunately I know someone whose girlfriend got killed near that same roundabout.
I dont even think its common knowledge, other than "watch the traffic".
Its actually quite shocking they even allowed the traffic to get that bad, it is after all "meant" to be the brightest minds in the country ( or was at some point).
It's generally hard for any existing city (especially if it is older one with narrow streets) to transform communication, from cost to having to displace citizens in worst case.
No wait yeah lets do what you thought would be the only solution, stop people moving into the city, nice one mate.