There are not enough bike lanes in this country. It’s bloody shameful to be honest. Visit other European countries and there will more often than not be some proper cycle paths. That doesn’t exist here to the same extent, if at all. This would be the number one way to reduce casualties.
Then there is definitely NOT enough police presence/checks on the roads. Christ, in the two years in drove a car in Sweden I got stopped 3 times for breathalyzing tests, never happened here.
I still say the biggest reason for casualties is that cyclists have to mix with cars on the roads. And when I say cycle paths i don’t mean a green painted strip on the road, but proper separated bits.