Of the 3,558 people impaired drivers killed in 2009 (not counting the drivers themselves), __________ deaths were preventable.

Impaired driving is a term that refers to the dangerous type of driving behavior of some drivers which is not appropriate or safe to drive a car or vehicle. Impaired driving can be due to several factors some of which are:

The driver has drunk excessive amount of alcohol or illegal drugs.
The driver slept during driving due to less sleep last night.
Driver got distracted while driving due to factors like calling while driving, texting etc.
Driver was suffering from a health issue due to which he was not supposed to drive or was in a safe condition but still he drove.

All such factors come under the category of impaired driving and can cause serious road accidents which have taken the lives of around 3,558 during 2009.

So, this looks very clear that all deaths were preventable if the drivers had not practiced impaired driving or they were well aware of the consequences and ethics and regulations of driving not for their own safety but the safety of their loved ones and fellow passengers as well.

Hope it help!