Why you should always assume the driver has not seen you

but full speed for cars is a very different thing to full speed for bikes. Roundabouts work best when all vehicles move at similar speeds so it's often safest for bicycles to sprint onto them. Yes, in this particular case we can see he could have avoided the accident by slowing down on approach to the roundabout, but only with hindsight do we know that. The car ahead that took the route he was taking was probably going just as fast.

Yes full speed for a car is higher than a bike but both need to moderate their speed for the situation. The fact the other car was going just as fast doesn't make it right!