I purchased a helmet from LBS for twice what helmets usually go for at Walmart.

At first I thought I got ripped off but when I really looked at the bike helmets from Walmart they were about half as thick as my helmet (I'm talking about the EPS).

Does this mean I actually got a good deal? More foam = more protection right? I hate how the CPSC doesn't bother to break down helmet ratings and simply issues a pass/fail. I wish testing like how the IIHS does with vehicles were conducted ...

Actually, higher price helmets tend to fit in one of the following (or more). Ignoring just buying at a more expensive place.

1) Lighter
2) Better air flow (cooler head)
3) Better retention systems
4) More aerodynamic
5) More "cool" factor... i.e. all the cool guys and gals wear them.
6) Constructed on machines run by high end artisan helmet constructeurs.

Common sense and logic dictate the fact the thicker the foam, the better "G" mitigation it will perform.

I guess it does stand to reason that helmets will perform differently based on construction, but I simply have no idea what-- and forgive the pun-- those break points are. I certainly hope to never find out the hard way. Better reporting from certification bodies would be nice, because yeah, it seems to come down to style, primarily, at this point.

Agree with the first 3 points, After that cynicism kicks in.
I always buy helmets based fit, and safety. After that, I hope to find decent ventilation. If aerodynamics results in poor ventilation, I pass. Cool factor? You should see a picture of me wearing the original Bell Biker helmet, Dorky then, Dorky now.
I have always hoped that by wearing a helmet I would improve my chances of keeping myself mentallly intact if I had a bad crash

Foam compresses when impacted. Helmet impacts ground and compresses for simple example 3 mm of the foam on the outside of the helmet. Head impacts the inside of the foam and compresses for example 3 mm of the foam. The foam thickness between these 2 points is unaffected. If a cheap helmet has adequate thickness for there to be an area between these points not to crush, then making it thicker does not result in better energy absorption. If a cheap helmet is thinner to where there is no area between these points, then a thicker foam would be "more protection."

Better than thickness would be to change the material. EPP has much higher energy absorption properties than EPS. But if EPS is adequate in absorption properties for head impact, then a more expensive and heavier material still doesn't make "more protection." Thus, EPS is used in helmets for the weight property. At I am guessing less than $1.00/lb for EPS (I extrude, expand, and mold EPP and EPE, no experience manufacturing or selling EPS), you are paying for the shape design of the "better" helmet for the first 3, reasons listed above in Little Darwin's post.

What's your favorite helmet? The new Giro Synthe helmets look really nice, and I'm a newby who hates his current Bell thick dorky helmet.

Maybe, maybe not. Depends on the quality, density, etc of the foam. Price is no guarantee.

I buy what is comfortable and fits me. The best helmet is the one that is worn and worn properly, if you are going to wear a helmet.

The CSPC standards are pretty low. Years ago there was the Snell certification, to the best of my knowledge it isn't used by bicycle helmet manufacturers any more.

Aaron