A story at: http://www.ttnews.com/articles/basetemplate.aspx?storyid=22391 tells of the new NHTSA rule for truck stopping distances.
Beginning in 2011, new trucks have to be able stop within 250 feet at 60 mph when loaded. This shaves 105 feet off the old standard, and brings trucks much closer to the stopping ability of automobiles. According to a chart at: http://www.jmu.edu/safetyplan/vehicle/generaldriver/stoppingdistance.shtml it will take an automobile around 185 feet at the same 60 mph. These figures do not include reaction time etc. — they’re only actual braking distances, and on a dry road surface.
Even though this new standard is going to be a major improvement, it’s still going to take a truck 65 feet more than a car to stop at that speed — in other words, about a truck length. This means that getting in front of a truck and slamming on the brakes will still be one of those mistakes that you only get to make once.
According to the cited article, there are already trucks on the road that can meet or exceed the new standard. Hopefully, this new regulation will inspire brake system engineers to go even further improving stopping distances.