The speakers disagree on this statement. Steven agrees that social drinkers pose a substantial threat, and this is reason for advocating the legal limit to be cut in half. Miguel disagrees and thinks heavy drinkers are the most important aspect of the drunk driving problem.

Neither speaker states an opinion on this statement. Both speakers think that a driver’s blood alcohol level affects their ability to drive safely, but neither says whether this is a direct correlation or if there's some other relationship.

The speakers agree on this statement. Steven thinks that the limit should be even lower. Miguel states that heavy drinkers who drink well beyond the limit are the most significant threat to the public.

Miguel does not express an opinion on this statement. Miguel only thinks that cutting the current level in half would not sigificantly improve highway safety. It's still possible that he thinks some light drinkers are dangerous.

Neither speaker expresses an opinion on this statement. We don’t know whether either speaker believes that there are any drivers that pose no danger to the public.