100% of transportation-related incidents are preventable, full stop. You can always stay home. Beyond that, it's a question of how we balance a number of factors such as risk and quality of life.
Just because someone failed to take certain steps to prevent an accident, it doesn't mean that they deliberately caused the accident.
By this reading, the author is probably saying that unless your car malfunctions and prevents you from stopping or steering, or there is some equivalent fluke happening (a deer darts out in front of you and you physically can't stop in time), then "accidents" are caused by negligence (not checking lanes when changing, playing with the radio, not looking for pedestrians) or malfeasance (unsafe passing, driving at an unsafe speed for the conditions, drunk driving).
I have mixed feelings about this, but I've been driving a while and I've seen a lot of truly stupid and/or mean spirited and/or reckless behavior that could quite predictably result in a collision, but it'd be a stretch to call the sad and obvious outcome an 'accident'.
> What is your state or city doing to address this safety issue and prevent severe injuries and fatalities?
So the negligent party is implied not to be the individual driver who is not giving due care and attention, but the road designer or maintainer for not making the road safer.
I agree that crashes often occur due to the direct negligence of a road user, but when it comes to the state, there are a lot of tradeoffs and calculations to make. They are not responsible for each individual accident, but for the overall outcome of road use in general. It's erroneous to say the state is negligent for (e.g) funding emergency services to improve outcomes after a range of incidents both on and off the road, vs. Road safety measures. If £X of extra ambulance and fire funding prevents Y road-related deaths and Z other deaths, whilst that same sum on road safety measures only prevents those Y road deaths, then cure may be better than prevention.