Recently Harvard had completed a fairly comprehensive report on Americans with their guns. One of the topics was about aggressive driving. Over 2,400 drivers responded.
The major findings found that persons with guns were more likely to engage in road rage. It also found that the ones with guns were also typically young adult males, binge drinkers, or persons previously arrested for non-traffic violations.
Comparing with NHTSA this group of drivers would be an exact match for those involved in fatalities where speeding and drunk driving were involved.
In 2005 MonkeyMeter.com ran a poll about how many of you carry a gun in your car. Here are the results.
Total votes: 282
Do you think guns should be allowed be kept in cars? Stay tuned for this poll. Also, I read another study that drivers who legally carry guns in their car by having a permit are typically very law abiding, and don't reflect the behavior of young road ragers with a gun.