A at risk driver would be a driver that "would have the greatest chance of getting into a car accident." At risk driver would be a person what took medication before driving which would causes sleepiness, raging, and also what can affect your eye sight, also people who are paying attention else where, or having arguments with other drivers is most likely to get into a car accident which is a "at risk" driver. A safe driver would do the opposite of the following.
Hope this helps!