Recently we've been receiving more than the usual number of press releases and samples of new helmets that meet only Department of Transportation (DOT) standards. Many people that I talk to about these lids claim that "a DOT-only helmet is better, because a Snell-approved helmet is too stiff." Their argument almost always cites Motorcyclist magazine's article from a couple years ago ("Blowing the Lid Off," June '05) in which a number of helmets were tested for impact absorption. Motorcyclist found that helmets meeting only the DOT standard were softer than Snell helmets (the other generally used standard in the United States), transmitting less impact energy in drop tests. Because of this the article con-cluded that DOT-only helmets were safer.
While I don't have an issue with the data presented in the article, I think it's a mistake for people to use it to make the blanket statement that a DOT-only helmet-any DOT-only helmet-is inherently safer than a helmet certified by Snell. I won't argue that one standard or another is better based on impact testing-that is a sticky issue in the industry and something that would take many pages to explain and discuss. But even with that out of the equation, there are a number of aspects that determine the safety of a helmet; the density of the shell and liner is just one of those.
Helmets sold in the U.S. for street use must meet the criteria of Federal Motor Vehicle Safety Standard (FMVSS) 218, the official DOT standard. Like any other products manufactured to DOT standards such as lights, turn signals and wheels, a helmet model is not actually tested or certified to meet FMVSS 218 before it can be sold; the honor system is used. It's up to the manufacturer to test whatever is necessary to determine if the helmet meets the standard and then label it thus. The DOT, through the National Highway Traffic Safety Administration (NHTSA ), relies on independent, random testing of helmets obtained from retail outlets to police the standard. What this means is that I could make helmets from papier mach here in my office, put DOT labels on the back and sell them on eBay as meeting the DOT standard. Everything would be fine and no one would know otherwise until the helmets were chosen for random testing-if they were even chosen. Snell, on the other hand, tests and certifies sample helmets before they are released to the public, in addition to conducting random sampling. The Snell sticker affixed to the liner means the helmet model has in fact passed the tests and is approved by the Snell Foundation. Judging from the list of helmets that fail the random NHTSA testing and are recalled each year (see www.nhtsa.dot.gov/cars/testing/comply/fmvss218), a DOT sticker on a helmet is certainly no guarantee that it meets the standard.
Another difference between Snell and DOT is the area of the head covered. FMVSS 218 requires significantly less coverage than Snell, giving rise to "shorty" helmets that can leave a lot of your head exposed. Snell and other standards call for the shell to extend farther down the forehead and sides and back of the head, and Snell even requires a chin-bar test. One DOT-only full-face helmet we recently received has no expanded polystyrene (EPS) liner in the sides or chin bar, just comfort padding that won't offer much protection in a fall. Snell calls for even more testing of additional safety features that DOT overlooks: a roll-off test, in which the helmet can't be removed with the chin strap done up, and a face-shield penetration test.
Now I'm not saying all DOT-only helmets are unsafe. On the contrary, many companies realize these shortcomings in the standard and manufacture their products accordingly. A premium-brand DOT-only helmet will have an EPS liner in the chin bar and sides, for instance, as well as other features that a cut-rate helmet won't.
Here's another example: Many helmets are showing up with elaborate venting, scoops and even lights now, and protrusions such as these can catch on something in a fall and cause serious damage. DOT limits these projections to 5mm in height, although I've seen helmets that have vents blatantly taller. The Economic Commission of Europe (ECE) standard has a test for projections and surface friction in which anything that can potentially jerk the helmet when it slides across a surface breaks away so as not to cause harm. While Snell doesn't have an equivalent test, premium-brand manufacturers will incorporate the ECE test into their own internal standards.
What does all this mean? If you consider the DOT standard to be safer in terms of impact protection and want to wear a DOT-only helmet, choose something from a reputable manufacturer and make sure that standards haven't been compromised in other areas. The DOT helmet may not be as protective overall as a comfortable, good-fitting lid that is certified by Snell or another organization.
