This is a controversial topic. It causes many arguments and not a little distress to those involved. I sincerely don't mean to cause anyone any upset, but I will always argue that there is no such thing as a dangerous road, only drivers who don't make the right decisions.
Back in the day when my job was to supervise and investigate serious or fatal road traffic collisions, I spent day in day out going to the scenes of crashes.
The collisions that fascinated me above any others were those involving just one vehicle and one driver, with no other cars being involved at all.
Overwhelmingly, these collisions were the result of driver error. They were caused by bad decisions based on a lack of perception of the reality of the environment.
Very, very few of these collisions were unavoidable and not down to driver error. In 30 years I remember just a handful, despite attending or seeing reports on hundreds and hundreds of them. Arguably, you could say that all of them were down to driver error, but perhaps that's taking too narrow a view.
Certainly, even the Government state that at least 70% of these collisions were caused solely by the driver. I'm not convinced, I think the figure is much higher. I can only surmise, but my guestimate would be that around 95% of them are absolutely attributable to driver error.