This is one of those areas, however, where what the criminal law requires and does not require does not pair up evenly with how civil liability works with respect to car and truck accidents.
The basic principle of civil liability in these sorts of cases is that motorists, especially commercial truckers, have to take reasonable care to operate their vehicles safely and not cause accidents.
Recent studies have shown that, in this respect, .08 is really more of a legal line in the sand than anything else. In other words, it makes sense why in the civil law, a truck driver can still be accountable for drunk driving even if the trucker blew under .08.
For instance, according to one analysis, a person who blows .05 BAC, which for a typical person is about three alcoholic drinks, will experience difficulty with coordination and, more specifically, controlling one's vehicle.
A blood alcohol content at this level could also mean that the driver will have a hard time focusing on moving objects, including other vehicles, and will not be able to effectively respond to a sudden change in road conditions.
This may be the reason why many truck drivers in the area, particularly those who travel back and forth over the Ohio River, are subject to a lower .04 BAC. Even if they do not face criminal charges, they may lose their ability to operate vehicles if caught with over .04 BAC. Likewise, should a trucker cause an accident while in violation of this stricter rule, they may be held accountable via a civil lawsuit.