What makes certain car accessories unsafe (or even illegal)?

From cuts and bruises to more serious injuries, many bad things can happen to the human body, and unfortunately, many of these can take place in a car. It's the job of manufacturers, governments and consumers' common sense to ensure that they don't.

Along these lines, the following three factors can make seemingly benign car accessories into deadly weapons. First, projectiles: While Mythbusters debunked the myth of the killer Kleenex box projectile, there are plenty of other accessories that can, will and do fly around the car, wreaking havoc during crashes. Ask yourself -- will your dash attachment or mini microwave really stay put when your car flips at 60 miles (96.5 kilometers) per hour, and if not, would you mind being hit in the head with it?

Second, distractions can also be deadly. Your hands-free smart phone interface, GPS, baseball-player bobble-head or even cup holder can distract you from the 12-prong buck standing on the double-yellow line. About those prongs: They're pointy, and you'd really rather not have them through your windshield. Even a newfangled smart device can create more distraction than ease if you're not comfortable with how to use it. Do your homework. And avoid things that are meant to distract you, like the dash-mounted DVD player. For truly terrifying (but also totally fascinating) statistics about distracted driving, visit the Web site of the University of Utah's Applied Cognition Lab.

A third factor that makes many car accessories unsafe is blocked line of sight. Similar to distracted driving, in which you aren't looking at things and thus hit them (or are hit by them), blocking your line of sight with feathered rearview talismans or tinted back windows can help ensure that you don't see things, with the same results. Car manufacturers go to great lengths to ensure that you can see your blind spots with a quick over-the-shoulder glance and have an unobstructed view of the 180 degrees in front of you. Don't spoil all their hard work by hanging fuzzy dice in your line of sight.

Next, let's look at how the government is trying to help protect you from unsafe accessories.